You don’t have anything inside the message itself that can be used for routing? This would be a content based routing scenario. Typically, the message type (root node and namespace) are used for this purpose. But you can use any property you want to promote for message routing or use extended properties from the adapter like File Name or SOAP Headers.
If there is nothing inside the message then I’m not sure how either place would really be able to determine were the message goes.
Hope this helps.