2 position hierarchy at a time

Hi All

We are using Position hierarchy

My Requirement is

Normal PO should go to approval in this hierarchy

 

  

Approving Seq	Postion/ user
1	X
2	B
3	C
4	D

For PO With DFF value of of Tender- Po Approval should go like this

  

Approving Seq	Postion/ user
1	A
2	B
3	C

B and C are comman user in both Hierarchy. I Have made to hierarchy and User has to manually choose the Hierachy while going for approval .

With this set up my Normal PO is also getting approved by User C. I guess because of Approval group of C.

How can i Achieve my requirement.