This is what I did.
I created a schema in my biztalk project. I then promoted some of the properties. In my case,
HeaderSchema.xsd where I had promoted MessageType and EventType.
Then I created multipart messages for each of the incoming branches’ receive shape and added this schema to be one of the parts, besides the actual message that I will be receiving in that receive shape.
Then, in the receive shape I added filter expression, where I said MessageType==\”something1\” AND EventType==\”something2\” for receive shape in the first branch and, MessageType==\”something3\” AND EventType==\”something4\” for receive shape in the second branch and so on for each branch’s receive shape.
You can then publish the orchestration as a web service and then while calling the webmethod add another paramter, which is of type header schema and enter your values there. For the first method (branch 1) set the property values of the header schema object to be MessageType==\”something1\” and EventType==\”something2\”, then set this value for each and every web method call. This way the listen shape will know which branch to forward it to based on the filter specified in the receive shape.
Hope that helps. I know this is not the greatest way to do this, however with the limitations in documentation and help from microsoft on this sucker \”BizTalk\” this is all we could come up with.