How to prevent a user from delegating an approval to another employee who is at a lower job level.

Summary:

Our Client has a requirement that a certain approver should be prevented from delegating the approval to another who is at a lower Job level than the approver.

Content (required):

Business Case: In the Client system currently, the Job level is tied to a certain dollar amount within which they are allowed to approve requests. A request exceeding the dollar amount will be requiring another level of approval from an approver at a higher level than the previous approver.

So for this, they want the system (Oracle) to prevent an approver to delegate the request to another employee who is at a lower job level than him, as his/her approval dollar amount available would be lower than him.