====== adv.callGroup ======
call.adv.callGroup is a boolean property that controls if new calls should automatically become part of a group call after established or not.

If call.adv.callGroup=true the call will be added to current group call as soon as it has been connected.

===== Value =====
Boolean:
  * true - add call to group call after it is connected
  * false - normal call

===== Usage =====
You may set call.adv.callGroup=true before calling call.answerCall() to make an incoming call automatically be added to the current group call.

When making new calls use [[ixnx:wrtc:js:api:wrtc:call|wrtc.call(..., {callGroup:true})]] instead.

After call has been established do not change value of call.adv.callGroup