Two realms on the same address

In this thread:

http://community.acmepacket.com/t5/SIP-Trunking-and-Interconnect/Sharing-One-Physical-Interface-With-Multiple-Realms/m-p/12574#M1314

 

there is a discussion on having multiple realm on the same network-interface.

 

I wan't to do kind of the same, but without having a separate sip-interface and steering-pool for each realm, so in fact have two different realms sharing the same address. The purpose is to direct calls via different realms with different parameter settings, but use the same source address for all.

 

Is this possible and, if yes, what realm will be used for incoming traffic to that address?