2 BoMs for a Material-1st BoM for Sub-Contracting & 2nd BoM for Production?

Hi Guys

My Client wants to have 2 BoMs for a Material

One BoM for Sub-Contracting and other BoM for In-house prodution.

If MRP is run, the system needs to trigger:

a) the 1st BoM for Sub-Contracting Purchase Order

b) the 2nd BoM for Production Order

as per the requirement.

How should i configure to this.??

Rush answers ASAP !!

cheers

MaruthiRam