How can the 'AOR' be used to to know which executive assistant is assigned to which manager?

Summary:

We are doing security implementation for a client. There is a specific role- 'Executive assistant' which requires access to be able to submit timecards on behalf of specific managers.

Content (required):

There are multiple executive assistants and multiple managers which makes it difficult to identify which executive assistant is assigned to which manager. These executive assistants may or may not be from the same department as their reporting manager. In that case, how can the 'AOR' be used to to identify which executive assistant is assigned to which manager and can submit timecard on behalf of that manager? Is their any other way the system can identify the executive assistants and their assigned managers...?