Inbound EDI map

Experts,

Wanted to know the approach to map an inbound EDI file to post into SAP. EDI inbound X12 file can contain data for more than one transaction. For example, it can have data for two sales order (two ST 850 envelopes ) or it can contain data for data for two separate transactions (Inbound Sales Order 850 and Inbound 945 shipping).

In these examples, XI has two create two transactions from one single file (two sales order or one sales order and one shipping). How should the mapping done ? Do I need to use BPM, custom ABAP/JAVA map etc ?

-Thanks

Bob