diff --git a/wled00/cfg.cpp b/wled00/cfg.cpp
index 2214584c..b345a873 100644
--- a/wled00/cfg.cpp
+++ b/wled00/cfg.cpp
@@ -240,6 +240,7 @@ bool deserializeConfig(JsonObject doc, bool fromFS) {
   CJSON(receiveNotificationBrightness, if_sync_recv["bri"]);
   CJSON(receiveNotificationColor, if_sync_recv["col"]);
   CJSON(receiveNotificationEffects, if_sync_recv["fx"]);
+  CJSON(receiveGroups, if_sync_recv["grp"]);
   //! following line might be a problem if called after boot
   receiveNotifications = (receiveNotificationBrightness || receiveNotificationColor || receiveNotificationEffects);
 
@@ -252,6 +253,7 @@ bool deserializeConfig(JsonObject doc, bool fromFS) {
   CJSON(notifyHue, if_sync_send["hue"]);
   CJSON(notifyMacro, if_sync_send["macro"]);
   CJSON(notifyTwice, if_sync_send[F("twice")]);
+  CJSON(syncGroups, if_sync_send["grp"]);
 
   JsonObject if_nodes = interfaces["nodes"];
   CJSON(nodeListEnabled, if_nodes[F("list")]);
@@ -594,6 +596,7 @@ void serializeConfig() {
   if_sync_recv["bri"] = receiveNotificationBrightness;
   if_sync_recv["col"] = receiveNotificationColor;
   if_sync_recv["fx"] = receiveNotificationEffects;
+  if_sync_recv["grp"] = receiveGroups;
 
   JsonObject if_sync_send = if_sync.createNestedObject("send");
   if_sync_send[F("dir")] = notifyDirect;
@@ -602,6 +605,7 @@ void serializeConfig() {
   if_sync_send["hue"] = notifyHue;
   if_sync_send["macro"] = notifyMacro;
   if_sync_send[F("twice")] = notifyTwice;
+  if_sync_send["grp"] = syncGroups;
 
   JsonObject if_nodes = interfaces.createNestedObject("nodes");
   if_nodes[F("list")] = nodeListEnabled;
diff --git a/wled00/data/settings_sync.htm b/wled00/data/settings_sync.htm
index 3e42e35f..66e8b433 100644
--- a/wled00/data/settings_sync.htm
+++ b/wled00/data/settings_sync.htm
@@ -1,23 +1,86 @@
 <!DOCTYPE html>
 <html lang="en"><head><meta name="viewport" content="width=500"><meta charset="utf-8"><title>Sync Settings</title>
 <script>var d=document;
+function gId(s)
+{
+  return d.getElementById(s);
+}
 function H(){window.open("https://github.com/Aircoookie/WLED/wiki/Settings#sync-settings");}function B(){window.open("/settings","_self");}
 function adj(){if (d.Sf.DI.value == 6454) {if (d.Sf.DA.value == 1) d.Sf.DA.value = 0; if (d.Sf.EU.value == 1) d.Sf.EU.value = 0;}
                else if (d.Sf.DI.value == 5568) {if (d.Sf.DA.value == 0) d.Sf.DA.value = 1; if (d.Sf.EU.value == 0) d.Sf.EU.value = 1;} }
-function SP(){var p = d.Sf.DI.value; d.getElementById("xp").style.display = (p > 0)?"none":"block"; if (p > 0) d.Sf.EP.value = p;}
-function SetVal(){switch(parseInt(d.Sf.EP.value)){case 5568: d.Sf.DI.value = 5568; break; case 6454: d.Sf.DI.value = 6454; break; case 4048: d.Sf.DI.value = 4048; break; }; SP();}
+function FC()
+{
+  for(j=0;j<8;j++)
+  {
+    gId("G"+(j+1)).checked=gId("GS").value>>j&1;
+    gId("R"+(j+1)).checked=gId("GR").value>>j&1;
+  }
+}
+function GC()
+{
+  var a=0, b=0;
+
+  var m=1;
+  for(j=0;j<8;j++)
+  {
+    a+=gId("G"+(j+1)).checked*m;
+    b+=gId("R"+(j+1)).checked*m;
+    m*=2;
+  }
+  gId("GS").value=a;
+  gId("GR").value=b;
+}
+function SP(){var p = d.Sf.DI.value; gId("xp").style.display = (p > 0)?"none":"block"; if (p > 0) d.Sf.EP.value = p;}
+function SetVal(){switch(parseInt(d.Sf.EP.value)){case 5568: d.Sf.DI.value = 5568; break; case 6454: d.Sf.DI.value = 6454; break; case 4048: d.Sf.DI.value = 4048; break; }; SP();FC();}
 function S(){GetV();SetVal();}
 function GetV(){var d=document;}
 </script>
 <style>@import url("style.css");</style></head>
 <body onload="S()">
-<form id="form_s" name="Sf" method="post">
+<form id="form_s" name="Sf" method="post" onsubmit="GC()">
 <div class="helpB"><button type="button" onclick="H()">?</button></div>
 <button type="button" onclick="B()">Back</button><button type="submit">Save</button><hr>
 <h2>Sync setup</h2>
 <h3>WLED Broadcast</h3>
 UDP Port: <input name="UP" type="number" min="1" max="65535" class="d5" required><br>
-2nd Port: <input name="U2" type="number" min="1" max="65535" class="d5" required><br>
+2nd Port: <input name="U2" type="number" min="1" max="65535" class="d5" required><br><br>
+<input name="GS" id="GS" type="number" style="display: none;"> <!-- hidden inputs for bitwise group checkboxes -->
+<input name="GR" id="GR" type="number" style="display: none;">
+<table style="margin: 0 auto;">
+    <tr>
+        <td>Sync groups</td>
+        <td>1</td>
+        <td>2</td>
+        <td>3</td>
+        <td>4</td>
+        <td>5</td>
+        <td>6</td>
+        <td>7</td>
+        <td>8</td>
+    </tr>
+    <tr>
+        <td>Send:</td>
+        <td><input type="checkbox" id="G1" name="G1"></td>
+        <td><input type="checkbox" id="G2" name="G2"></td>
+        <td><input type="checkbox" id="G3" name="G3"></td>
+        <td><input type="checkbox" id="G4" name="G4"></td>
+        <td><input type="checkbox" id="G5" name="G5"></td>
+        <td><input type="checkbox" id="G6" name="G6"></td>
+        <td><input type="checkbox" id="G7" name="G7"></td>
+        <td><input type="checkbox" id="G8" name="G8"></td>
+    </tr>
+    <tr>
+        <td>Receive:</td>
+        <td><input type="checkbox" id="R1" name="R1"></td>
+        <td><input type="checkbox" id="R2" name="R2"></td>
+        <td><input type="checkbox" id="R3" name="R3"></td>
+        <td><input type="checkbox" id="R4" name="R4"></td>
+        <td><input type="checkbox" id="R5" name="R5"></td>
+        <td><input type="checkbox" id="R6" name="R6"></td>
+        <td><input type="checkbox" id="R7" name="R7"></td>
+        <td><input type="checkbox" id="R8" name="R8"></td>
+    </tr>
+</table><br>
 Receive: <input type="checkbox" name="RB">Brightness, <input type="checkbox" name="RC">Color, and <input type="checkbox" name="RX">Effects<br>
 Send notifications on direct change: <input type="checkbox" name="SD"><br>
 Send notifications on button press or IR: <input type="checkbox" name="SB"><br>
diff --git a/wled00/html_settings.h b/wled00/html_settings.h
index 4d02814f..5b253156 100644
--- a/wled00/html_settings.h
+++ b/wled00/html_settings.h
@@ -237,20 +237,35 @@ type="button" onclick="Save()">Save</button></form></body></html>)=====";
 // Autogenerated from wled00/data/settings_sync.htm, do not edit!!
 const char PAGE_settings_sync[] PROGMEM = R"=====(<!DOCTYPE html><html lang="en"><head><meta name="viewport" content="width=500">
 <meta charset="utf-8"><title>Sync Settings</title><script>
-var d=document;function H(){window.open("https://github.com/Aircoookie/WLED/wiki/Settings#sync-settings")}function B(){window.open("/settings","_self")}function adj(){6454==d.Sf.DI.value?(1==d.Sf.DA.value&&(d.Sf.DA.value=0),1==d.Sf.EU.value&&(d.Sf.EU.value=0)):5568==d.Sf.DI.value&&(0==d.Sf.DA.value&&(d.Sf.DA.value=1),0==d.Sf.EU.value&&(d.Sf.EU.value=1))}function SP(){var e=d.Sf.DI.value;d.getElementById("xp").style.display=e>0?"none":"block",e>0&&(d.Sf.EP.value=e)}function SetVal(){switch(parseInt(d.Sf.EP.value)){case 5568:d.Sf.DI.value=5568;break;case 6454:d.Sf.DI.value=6454;break;case 4048:d.Sf.DI.value=4048}SP()}function S(){GetV(),SetVal()}function GetV() {
+var d=document;function gId(e){return d.getElementById(e)}function H(){window.open("https://github.com/Aircoookie/WLED/wiki/Settings#sync-settings")}function B(){window.open("/settings","_self")}function adj(){6454==d.Sf.DI.value?(1==d.Sf.DA.value&&(d.Sf.DA.value=0),1==d.Sf.EU.value&&(d.Sf.EU.value=0)):5568==d.Sf.DI.value&&(0==d.Sf.DA.value&&(d.Sf.DA.value=1),0==d.Sf.EU.value&&(d.Sf.EU.value=1))}function FC(){for(j=0;j<8;j++)gId("G"+(j+1)).checked=gId("GS").value>>j&1,gId("R"+(j+1)).checked=gId("GR").value>>j&1}function GC(){var e=0,d=0,n=1;for(j=0;j<8;j++)e+=gId("G"+(j+1)).checked*n,d+=gId("R"+(j+1)).checked*n,n*=2;gId("GS").value=e,gId("GR").value=d}function SP(){var e=d.Sf.DI.value;gId("xp").style.display=e>0?"none":"block",e>0&&(d.Sf.EP.value=e)}function SetVal(){switch(parseInt(d.Sf.EP.value)){case 5568:d.Sf.DI.value=5568;break;case 6454:d.Sf.DI.value=6454;break;case 4048:d.Sf.DI.value=4048}SP(),FC()}function S(){GetV(),SetVal()}function GetV() {
 %CSS%%SCSS%</head><body onload="S()"><form
- id="form_s" name="Sf" method="post"><div class="helpB"><button type="button" 
-onclick="H()">?</button></div><button type="button" onclick="B()">Back</button>
-<button type="submit">Save</button><hr><h2>Sync setup</h2><h3>WLED Broadcast
-</h3>UDP Port: <input name="UP" type="number" min="1" max="65535" class="d5" 
-required><br>2nd Port: <input name="U2" type="number" min="1" max="65535" 
-class="d5" required><br>Receive: <input type="checkbox" name="RB">Brightness, 
-<input type="checkbox" name="RC">Color, and <input type="checkbox" name="RX">
-Effects<br>Send notifications on direct change: <input type="checkbox" 
-name="SD"><br>Send notifications on button press or IR: <input type="checkbox" 
-name="SB"><br>Send Alexa notifications: <input type="checkbox" name="SA"><br>
-Send Philips Hue change notifications: <input type="checkbox" name="SH"><br>
-Send Macro notifications: <input type="checkbox" name="SM"><br>
+ id="form_s" name="Sf" method="post" onsubmit="GC()"><div class="helpB"><button 
+type="button" onclick="H()">?</button></div><button type="button" onclick="B()">
+Back</button><button type="submit">Save</button><hr><h2>Sync setup</h2><h3>
+WLED Broadcast</h3>UDP Port: <input name="UP" type="number" min="1" max="65535" 
+class="d5" required><br>2nd Port: <input name="U2" type="number" min="1" 
+max="65535" class="d5" required><br><br><input name="GS" id="GS" type="number" 
+style="display:none"> <input name="GR" id="GR" type="number" 
+style="display:none"><table style="margin:0 auto"><tr><td>Sync groups</td><td>1
+</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr>
+<tr><td>Send:</td><td><input type="checkbox" id="G1" name="G1"></td><td><input 
+type="checkbox" id="G2" name="G2"></td><td><input type="checkbox" id="G3" 
+name="G3"></td><td><input type="checkbox" id="G4" name="G4"></td><td><input 
+type="checkbox" id="G5" name="G5"></td><td><input type="checkbox" id="G6" 
+name="G6"></td><td><input type="checkbox" id="G7" name="G7"></td><td><input 
+type="checkbox" id="G8" name="G8"></td></tr><tr><td>Receive:</td><td><input 
+type="checkbox" id="R1" name="R1"></td><td><input type="checkbox" id="R2" 
+name="R2"></td><td><input type="checkbox" id="R3" name="R3"></td><td><input 
+type="checkbox" id="R4" name="R4"></td><td><input type="checkbox" id="R5" 
+name="R5"></td><td><input type="checkbox" id="R6" name="R6"></td><td><input 
+type="checkbox" id="R7" name="R7"></td><td><input type="checkbox" id="R8" 
+name="R8"></td></tr></table><br>Receive: <input type="checkbox" name="RB">
+Brightness, <input type="checkbox" name="RC">Color, and <input type="checkbox" 
+name="RX">Effects<br>Send notifications on direct change: <input 
+type="checkbox" name="SD"><br>Send notifications on button press or IR: <input 
+type="checkbox" name="SB"><br>Send Alexa notifications: <input type="checkbox" 
+name="SA"><br>Send Philips Hue change notifications: <input type="checkbox" 
+name="SH"><br>Send Macro notifications: <input type="checkbox" name="SM"><br>
 Send notifications twice: <input type="checkbox" name="S2"><br><i>
 Reboot required to apply changes.</i><h3>Instance List</h3>
 Enable instance list: <input type="checkbox" name="NL"><br>
diff --git a/wled00/json.cpp b/wled00/json.cpp
index eb02edbb..7d136d4a 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -22,7 +22,7 @@ void deserializeSegment(JsonObject elem, byte it, byte presetId)
     uint16_t len = elem[F("len")];
     stop = (len > 0) ? start + len : seg.stop;
   }
-  uint16_t grp = elem[F("grp")] | seg.grouping;
+  uint16_t grp = elem["grp"] | seg.grouping;
   uint16_t spc = elem[F("spc")] | seg.spacing;
   strip.setSegment(id, start, stop, grp, spc);
 
@@ -332,7 +332,7 @@ void serializeSegment(JsonObject& root, WS2812FX::Segment& seg, byte id, bool fo
     root["stop"] = seg.stop;
   }
 	if (!forPreset) root[F("len")] = seg.stop - seg.start;
-  root[F("grp")] = seg.grouping;
+  root["grp"] = seg.grouping;
   root[F("spc")] = seg.spacing;
   root[F("of")] = seg.offset;
   root["on"] = seg.getOption(SEG_OPTION_ON);
diff --git a/wled00/set.cpp b/wled00/set.cpp
index e34bf06b..5ab6c0d0 100644
--- a/wled00/set.cpp
+++ b/wled00/set.cpp
@@ -209,6 +209,10 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
     if (t > 0) udpPort = t;
     t = request->arg(F("U2")).toInt();
     if (t > 0) udpPort2 = t;
+
+    syncGroups = request->arg(F("GS")).toInt();
+    receiveGroups = request->arg(F("GR")).toInt();
+
     receiveNotificationBrightness = request->hasArg(F("RB"));
     receiveNotificationColor = request->hasArg(F("RC"));
     receiveNotificationEffects = request->hasArg(F("RX"));
diff --git a/wled00/udp.cpp b/wled00/udp.cpp
index 590d2540..d2391e16 100644
--- a/wled00/udp.cpp
+++ b/wled00/udp.cpp
@@ -4,13 +4,14 @@
  * UDP sync notifier / Realtime / Hyperion / TPM2.NET
  */
 
-#define WLEDPACKETSIZE 36
+#define WLEDPACKETSIZE 37
 #define UDP_IN_MAXSIZE 1472
 #define PRESUMED_NETWORK_DELAY 3 //how many ms could it take on avg to reach the receiver? This will be added to transmitted times
 
 void notify(byte callMode, bool followUp)
 {
   if (!udpConnected) return;
+  if (!syncGroups) return;
   switch (callMode)
   {
     case CALL_MODE_INIT:          return;
@@ -39,7 +40,8 @@ void notify(byte callMode, bool followUp)
   //0: old 1: supports white 2: supports secondary color
   //3: supports FX intensity, 24 byte packet 4: supports transitionDelay 5: sup palette
   //6: supports timebase syncing, 29 byte packet 7: supports tertiary color 8: supports sys time sync, 36 byte packet
-  udpOut[11] = 8; 
+  //9: supports sync groups, 37 byte packet
+  udpOut[11] = 9; 
   udpOut[12] = colSec[0];
   udpOut[13] = colSec[1];
   udpOut[14] = colSec[2];
@@ -72,6 +74,9 @@ void notify(byte callMode, bool followUp)
   uint16_t ms = tm.ms;
   udpOut[34] = (ms >> 8) & 0xFF;
   udpOut[35] = (ms >> 0) & 0xFF;
+
+  //sync groups
+  udpOut[36] = syncGroups;
   
   IPAddress broadcastIp;
   broadcastIp = ~uint32_t(Network.subnetMask()) | uint32_t(Network.gatewayIP());
@@ -219,6 +224,12 @@ void handleNotifications()
 
     //compatibilityVersionByte: 
     byte version = udpIn[11];
+
+    // if we are not part of any sync group ignore message
+    if (version < 9 || version > 199) {
+      // legacy senders are treated as if sending in sync group 1 only
+      if (!(receiveGroups & 0x01)) return;
+    } else if (!(receiveGroups & udpIn[36])) return;
     
     bool someSel = (receiveNotificationBrightness || receiveNotificationColor || receiveNotificationEffects);
     //apply colors from notification
@@ -263,7 +274,7 @@ void handleNotifications()
     }
 
     //adjust system time, but only if sender is more accurate than self
-    if (version > 7)
+    if (version > 7 && version < 200)
     {
       Toki::Time tm;
       tm.sec = (udpIn[30] << 24) | (udpIn[31] << 16) | (udpIn[32] << 8) | (udpIn[33]);
diff --git a/wled00/wled.h b/wled00/wled.h
index 4148478b..f02ebcb0 100644
--- a/wled00/wled.h
+++ b/wled00/wled.h
@@ -298,6 +298,8 @@ WLED_GLOBAL bool liveHSVCorrection _INIT(false);
 WLED_GLOBAL uint16_t liveHSVSaturation _INIT(13);
 WLED_GLOBAL uint16_t liveHSVValue _INIT(10);
 
+WLED_GLOBAL uint8_t syncGroups    _INIT(0x01);                    // sync groups this instance syncs (bit mapped)
+WLED_GLOBAL uint8_t receiveGroups _INIT(0x01);                    // sync receive groups this instance belongs to (bit mapped)
 WLED_GLOBAL bool receiveNotificationBrightness _INIT(true);       // apply brightness from incoming notifications
 WLED_GLOBAL bool receiveNotificationColor      _INIT(true);       // apply color
 WLED_GLOBAL bool receiveNotificationEffects    _INIT(true);       // apply effects setup
diff --git a/wled00/xml.cpp b/wled00/xml.cpp
index f87bf35d..c1d129f8 100644
--- a/wled00/xml.cpp
+++ b/wled00/xml.cpp
@@ -396,6 +396,8 @@ void getSettingsJS(byte subPage, char* dest)
   {
     sappend('v',SET_F("UP"),udpPort);
     sappend('v',SET_F("U2"),udpPort2);
+    sappend('v',SET_F("GS"),syncGroups);
+    sappend('v',SET_F("GR"),receiveGroups);
 
     sappend('c',SET_F("HX"),liveHSVCorrection);
     sappend('v',SET_F("HS"),liveHSVSaturation);
