Two position hierarchies for requisition Heirarchy ?

Hello,

We have 2 position heirarchies for requisitions.

Position Heirarchy A - for requisition approvals whose supplier is known

Position Heirarchy B - for requisitions whose supplier and supplier site is not known.

Is it possible to create a rule in Approval Management Engine, so that the requisitions are routed to the concerned heirarchy based on the existence of supplier ?

Regards,

Monika