Row Level Security with multiple factors

Hi,

I am trying to use RLS on a large dashboard with many, many tables.

Basically I have Employees who belong to contracts and I want the RLS to work such that someone assigned to that contract would see the data only relevant to their contracts.

There are some contractors that serve on multiple contracts but I am not sure how to set up the user roles.

I want people from Contract A to only be able to see Contract A, B to see B and so on.  

I tried using this [Contract] = LOOKUPVALUE(Contract[Contract],Contract[Contractor Email],USERPRINCIPALNAME())  but it will repeat Dennis and you should only be able to select one contract at a time.   Any insight would be greatly appreciated. Thanks