Change of INV Orgs / PO receiving data migration question?

Hello,

We are in the process of creating several new average costing Inventory Orgs within the existing setup and these Orgs will be used for receiving inventory via PO receipts.  The items assigned to existing Orgs (standard costing orgs) will have to be reassigned to these new Orgs, for us to be able to start using them for average costing.  We currently have a large number of approved and unapproved requisitions / purchase orders pending receipts and also partially receipted POs in the system which will need to be brought across to these new Orgs.  We can create the initial OH inventories etc