diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 0136e3656..a3a0880ee 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -15403,6 +15403,17 @@ This should be as low as possible, but too low may break functionality</string>
       <key>Value</key>
       <integer>44125</integer>
     </map>
+    <key>VoiceMultiInstance</key>
+    <map>
+      <key>Comment</key>
+      <string>Allow multiple viewers to have the voice enabled at the same time</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>
     <key>WLSkyDetail</key>
     <map>
       <key>Comment</key>
diff --git a/indra/newview/llappviewer.cpp b/indra/newview/llappviewer.cpp
index 2777da456..76ba4b9cb 100644
--- a/indra/newview/llappviewer.cpp
+++ b/indra/newview/llappviewer.cpp
@@ -2503,7 +2503,7 @@ bool LLAppViewer::initConfiguration()
 			// This is the second instance of SL. Turn off voice support,
 			// but make sure the setting is *not* persisted.
 			LLControlVariable* disable_voice = gSavedSettings.getControl("CmdLineDisableVoice");
-			if(disable_voice)
+			if(disable_voice && !gSavedSettings.getBOOL("VoiceMultiInstance"))
 			{
 				const BOOL DO_NOT_PERSIST = FALSE;
 				disable_voice->setValue(LLSD(TRUE), DO_NOT_PERSIST);
diff --git a/indra/newview/llvoiceclient.cpp b/indra/newview/llvoiceclient.cpp
index d7761909a..43a12d5c9 100644
--- a/indra/newview/llvoiceclient.cpp
+++ b/indra/newview/llvoiceclient.cpp
@@ -1313,7 +1313,16 @@ void LLVoiceClient::connectorCreate()
 	<< "<Request requestId=\"" << mCommandCookie++ << "\" action=\"Connector.Create.1\">"
 		<< "<ClientName>V2 SDK</ClientName>"
 		<< "<AccountManagementServer>" << mVoiceAccountServerURI << "</AccountManagementServer>"
-		<< "<Mode>Normal</Mode>"
+		<< "<Mode>Normal</Mode>";
+	
+	if (gSavedSettings.getBOOL("VoiceMultiInstance"))
+	{
+		stream
+			<< "<MinimumPort>30000</MinimumPort>"
+			<< "<MaximumPort>50000</MaximumPort>";
+	}
+
+	stream
 		<< "<Logging>"
 			<< "<Folder>" << logpath << "</Folder>"
 			<< "<FileNamePrefix>Connector</FileNamePrefix>"
@@ -1686,6 +1695,19 @@ void LLVoiceClient::stateMachine()
 						std::string args;
 						std::string cmd;
 						std::string loglevel = gSavedSettings.getString("VivoxDebugLevel");
+
+						// If we allow multiple instances of the viewer to start the voice
+						// daemon, set TEMPORARY random voice port
+						if (gSavedSettings.getBOOL("VoiceMultiInstance"))
+						{
+							LLControlVariable* voice_port = gSavedSettings.getControl("VoicePort");
+							if (voice_port)
+							{
+								const BOOL DO_NOT_PERSIST = FALSE;
+								S32 port_nr = 30000 + ll_rand(20000);
+								voice_port->setValue(LLSD(port_nr), DO_NOT_PERSIST);
+							}
+						}
 						
 						if(loglevel.empty())
 						{
@@ -1694,6 +1716,12 @@ void LLVoiceClient::stateMachine()
 						
 						args += " -ll ";
 						args += loglevel;
+
+						// Tell voice gateway to listen to a specific port
+						if (gSavedSettings.getBOOL("VoiceMultiInstance"))
+						{
+							args += llformat(" -i 127.0.0.1:%u",  gSavedSettings.getU32("VoicePort"));
+						}
 						
 						LL_DEBUGS("Voice") << "Args for SLVoice: " << args << LL_ENDL;