OU vs Inventory Org in iSupplier Portal

Hi,

Existing Org setup: We have an Operating Unit say US-01, which is also an Inventory Org.

Another Inventory Org say TO-01 is under US-01 Operating Unit.

Two Business Requirements:

1. Suppliers should be able to access all PO's related to TO-01 Inventory Org ONLY in iSupplilier Portal. How do we achieve this when TO-01 INv org is under US-01 OU/INV Org.

2. How do we generate Unique PO Numbers systematically in each of these US-01 and TO-01 Inventory Orgs? I do see this generated at the OU level ONLY.

Appreciate any help.

Thanks,

Bala