[PO] Item Not Found During Purchase Requisition (PR) Creation

In a Operation Unit (OU), I have 2 inventory organization (inventory child type), e.g. OrgA & OrgB. I need to raise a PR to purchase ItemC under OrgB. In Item setup, ItemC is created in Inventory Master org, and assigned to OrgB. Purchasable flag has been checked in both Inventory Master and OrgB. When i keyed in the item during PR creation, item not found, why?

The reason being the OrgA was assigned in Financial Options setup (Setup -> Organizations -> Financial Options), Supplier - Purchasing, Inventory Organization field. If OrgA is assigned, only item assigned to OrgA can be found in the LOV.

We can setup Inventory Master org in each OU, then assign the Inventory Master org in the Financial Options. From there, we can choose any items that was created under the Inventory Master org.