IDOC Header Record

Our scenario is File(s) ---> XI -

> IDOC

We are receiving 3 Different Files, with Employee information from 3 different Countries and using XI , the records will be posted into R/3. Each record from the file will be treated as an IDoc.

The File is going to contain the Header Record, followed by the Detail records.

The header record will determine from whom this file was sent and we need to map the header info with the Control record.

How can I achieve the above task of separating the Header Record and the other detail records in the Message Mapping.

I would Greatly appreciate the Help.