[Serusers] Multiple Invites

Hi, I am new to Ser, and hence I need some help on the following: 1. Someone makes a PSTN call and my cisco router forwards the call to my SER sip server. By default, my router will forward it to an account on SER, such as 1000. 2. Upon receiving the request, SER should make ALL registered phones in the same domain ring. When someone picks up the phone, other phones should stop ringing. I am able to implement point 1, but how can I make all phones ring at the same instance? I am thinking of doing something like the following for INVITES : if(uri =~"sip:1002@serproxy.com"){ rewriteuri("sip:1003@serproxy.com"); forward(uri:host, uri:port); rewriteuri("sip:1004@serproxy.com"); forward(uri:host, uri:port); } Can someone pls advise me on the best approach? Regards, zan