In multiple partner scenario who are sedning either similar or multiple EDI messages it is suggested to use Direct Binding.
Using Direct binding you can set the filter conditions at the Receive port. Thus as soon as the message is published to the Database depending on the filter condition the message will be picked up and processed.
For the party data validations you can extract ISA properties using BizTalk EDI context properties and compare them against the party configurations values stored in the EDI DBs.
Regards
Vishnu