Creation of Approval Hierarchy

 Hi,

I am in a process of creating an dynamic approval group for invoice approval. The situation is as discussed below. 

As per the org structure, we have 4 operating units, viz OP1, OP2, OP3, OP4 and these operating units are spread across 5 locations. LOC1, LOC2, LOC3,LOC4,LOC5

The exact relationship is as follows,

LOC1 --> OP1,OP2,OP3

LOC2 --> OP2,OP3

LOC3 --> OP3

LOC4 --> OP3,OP4,

LOC5 --> OP1

Now each location is having one finance department responsible for the available operating units at that location.

I want to create a hierarchy, so that the invoices from all the operating units at one location should go the person at that location even if the O.U is available at various locations.