Single Costing Organziation across multiple Operating Units

Hi,

We want to have following functionlity

We have Two Operating units
1. OU A
2. OU B

Under Each of the Operating Unit, We have 1 Inventory Organization
1. OU A
1.1 Inventory Org IO A1
2. OU B
2.1 Inventory Org IO B1

We already have Item master organziation as C for both the Organization.

For IO A1 and IO B1 we want Costing Organization as A.

We want to have Single organization (A) where the item costing insformation will be maintained and updated.