Routing using RFC 4904 - with TGRP & Trunk-Context in the Contact Header

Hi Fellows,

I would like if you can help me with the following.

I have a Control Switch connected to my SBC core where it is sending me INVITE from different trunk groups that I would like to route based in this core trunk group to specific SA's.

I was thinking use the RFC 4904 routing using tgrp and trunk context, but the issue is that INVITE from the CS the tgrp/trunk-context is comming in the CONTACT header and not in the Request-URI.

Could be possible to make a routing to the SA(tgrp:trunk-context) using this CONTACT ? how to suppose that SBC route the INVITE to the SA if is not coming in the Request-URI.