PO approvals where direct report and supervisor share the same approval limit

We are using standard position hiearchy approvals for POs and Requisitions in Purchasing. We have a scenario where two users (one is a direct report and one is the supervisor) both share the same approval limits. We've received a requirement to ensure that in this case, where both the direct report and the supervisor have the same approval limit, they are both required to approve the PO before the PO is considered approved. Is there a way to achieve this with standard functionality?