R12 - AME - Invoice Approval by code combination

 I am trying to use the functionality provided by AME and need some assistance. I am working on version 12.0.4

The process I am trying to create is:

AP enters Invoice header "requestor" and approval is initiated.    The approver then receives a notification and validates the coding on the invoice "lines".  If it is incorrect, the requestor changes it then "approves" the transaction.   (This part I have working).

I want the system to dynamically build the approvers list based on the code combination(s) for each line.

The problem is where do I capture the code combinations authorized for each approver.  We use multiple segments for approval (company - account - location - cost centre) which is why the "signing limits form" won't work for us.