How to determine EDI Sender’s logical address

Using the built-in EDI adapter, is there any message context property that contains the EDI logical address (in the form of EDI://1234567:ZZ:1234567) of the sender of a message?

I have one receive port with fifteen receive locations. All 15 receive locations are using the EDI adapter and the same EDI X12 document schema and envelope. I need to do routing and corellation based on who the message was from, but that information is getting stripped off before I can use it.

… no I don’t want to create 15 receive ports and then use the receiveportname as the routing property. I’d really like to do this the same way I use the MSMQ adapter… some kind of party resolution that populates the bts.sourceparty… any hints?