How to exclude a particular Subinventory in MO allocation for OPM WIP Issue

Hi Gurus,

We are in R12.1.3 and have a scenario where MO created from OPM Batch WIP Issue should not allocate from a WIP subinventory . Pls suggest your ideas.

Scenario explanation:

1. In PE Parameters> Yield subinventory = WIP and Supply subinventory = MAIN

2. Inventory picking rule is defined with sibinventory = MAIN for Transaction type = Backflush transfer

3. Raw Material stock with first expiry lot (soon expiry) is maintained in WIP subinventory and late expiry lots are in MAIN subinventory

4. During picking process from Batch, when MO is created, system applies FIFO and allocates quantity from WIP and then from MAIN sub inventory for the remaining qty