Classic Scenario PO has multiple OA Partner Functions for Vendor

Hi,

I have a 'design' issue. My R/3 Vendor has many OA Partner Functions for the different Branches they have and the PO needs to be Faxed to the OA Partner Function number, but the PO needs to be created against the VN Partner Function.

So, how do i do this in SRM? I was going to have a seperate Catalog link for each OA Partner function, but this is not creating the R/3 PO with VN Partner Function of the 'core' Vendor number.

Does anyone have any advice for this?

regards Adam

Using SRM 5.0 (Server 5.5) SP 8 and R/3 4.6C in Classic Scenario - my catalogs are external vendor.