File sender, dynamic interface

Hello,

we are receiving from many partners different messages (e.g. different idocs) in files. All files are stored in the same directory and the filename is only a date/time stamp.

So from this information I do not know anything about the payload.

How can I receive this files into XI by the fileadapter and to start teh correct receiver determination, allthough I do not know the sender (but which is in the payload) and the interface (all I know is that it is an IDOC).

My goal is, that I can maintain also different (Sender)Parties, as I require different Header Mappings for the IDOC adapter to R/3.

Who can help me???

best regards

Werner Magerl