Is it possible to create purchase documents in different Procurement BU to the negotiation?

Summary:

In testing I have performed it seems that, to automatically create PO from negotiation, the Procurement BU for the supplier site must match the negotiation Procurement BU. Therefore the purchase order will/must be created in the same procurement BU as the negotiation. Is this correct, even where service provider relationships are defined?

Content (required):

I have a requirement where the RFQ function is completely outsourced, and this function manages the RFQ process to award stage only.

However once the purchasing document is created, the responsibility is managed entirely by the in-house procurement team/buyers only.

From a security point of view it would be better to have the RFQ and PO in different procurement BUs, rather than trying to manage via specific procurement agent settings for a single Proc BU. I appreciate that would mean two supplier sites needed for the supplier (one in RFQ Proc BU and one in PO Proc BU).