Dynamic RLS for Regional Managers and Location Managers

Case:

A business has thousands of employees, hundreds of locations and several regions. I want to use company emails to set up dynamic RLS Roles for...

1. Executives (that will see everything).

2. Regional Managers (that will see only their respective regions).

3. Location Managers (that will see only their respective locations).

Some location managers are over more than one location and some regional managers are over more than one region. This occurs when the manager is covering for the absense of a manager at the other location or region.

Question:

How do I model this/set up this type of solution?

I have found a ton of information on setting up rls but havent been able to relate any to this specific instance. I can succesfully set up RLS for ONLY location managers or ONLY Regional managers but I have been unable to figure out how to use these roles together. 

Although these are likely not what I need for a functional solution, my current objects are as follows:

• Users
• community permissions
• region permissions
• community dimension
• region dimension
• fact table.