Routing Work Centers in Different BPs

We're on 9.1.  So we have an item that is currently manufactured in one branch (stocking type M) and has quality control as one of the work centers in the routing. That item is then purchased by another branch (stocking type P).  We're considering having the purchasing branch do the quality control step due to the need for more space.  Is there a way to do this without setting up WIP items?  I need all of the associated costs of manufacturing to be applied to Business Units where the process is actually taking place.

Ideas appreciated!  Thank you