Three Operating Units - Just One controls Purchasing

Hi -

assume that i have the following structure

- One Business Group

- One Legal Entity

- One Ledger

- Three Operation Units  (A , B and C) for example

- Three Inventory organisations

Lets Assume that Just operating unit (A) controls Purchasing for all the Entity.

For Example: 

1- Operating Unit (A) Send POs to suppliers With all the Entity Needs.

2- Suppliers Ship Items To other organizations (B , C ) directly .

How could that be done ?   If PO is made in operating Unit A .. i have to receive it in its own inventory organization first.

I want to make the PO in one operating unit and receive it directly in other..Is that possible ?