PO Approval routing option

Summary:

Business Case : For multiple BUs, there is single buyer who manages the purchase order but next approval should be varying based on the manager of respective business units.
e.g. Buyer XYZ manages purchase order 3 business unit Netherlands, Belgium and Austria. Once PO is submitted for approval, It should route to next approval based on the business unit .

We are using job level hierarchy and donot want to create 3 different approvals per business unit .

In the current state, PO for any business unit are getting routed to buyers manager though they are not responsible to approve for other two BUs.