Requisition Approval based on requestor rather than preparer

We have requisition preparers (various admins) who enter requisitions for other employees (their managers).  The current requisition approval hierarchy is being generated based on the preparer (the admin).  However, we would like the requisition approval hierarchy to be based on the requestor of the requisition (the manager) rather than the preparer who is entering it.

We are not using AME, nor do we want to implement that at this time.  Is there another way of implementing the above?

Thanks.