Delegation of approval rights

Dear all,

We have just purchase Oracle E-business suite and are in the midst of implementation. However, we are some queries on the delegation of approval rights.

PR and PO have to be approved by managers, however, when the managers are out of office, I understand that he/she can delegate his authority to approve PR/PO to another person. Is there any way to control or ensure that a manager can only delegate responsibiities to another user of the same managerial position? We have concerns that a manager delegate his responsibilities to someone of lower position and that things may get out of hand.