I need forking a call to multiple destinations in paralel on different network segments, requiring different rtpproxy parameters. Reading the rtpproxy module documentation I discovered that is possible by setting the "b" parameter on rtpproxy_manage(), rtpproxy_offer(), rtpproxy_answer() and rtpproxy_destroy() functions, but I'm with some doubts... 

I can't understanding how set the extra_id_pv parameter correctly to use when the "b" parameter is used.

The "b" parameter is supported on rtpproxy version 1.2.1?

Best Regards