How to Enable Multiple Approvers for Absence and TimeCards

Summary:

We are a financial institution and have many field locations. Each location could be comprised of a Manager and several Assistant Managers. Employees within the field location are assigned evenly among the Assistant Managers (AM). This means AM1 cannot see AM2's employees and vice versa. We found a workaround where if they delegate their roles to one another, they can see the employees and initiate transactions; however, this does not allow for approvals. And you can only delegate your approval to one person (per area) and you don't retain approval access.

I was thinking of Area of Responsibility, but that seems to be only for HR. Then I was looking at Matrix Managers, but that doesn't seem to include approvals.