RLS on two columns based on OR

Hi all - i've been searching online for most of this week to a solution but couldn't find one similar to my scenario.

I have two tables, Cases and Users. 

In Users, I have the email address the user will login with, including their Department.

In Cases, there are thousands of rows that include two columns, Originating Team and Resolving Team.

Now, I can create security roles for each Department individually using:

'Cases'[Originating Team] = "Department Name" || 'Cases'[Resolving Team] = "Department Name"

But this would mean adding hundreds of users individually to the security roles in the service.

Instead, I've been trying to use 'User'[User Name] = USERPRINCIPALNAME(), however, with my knowledge of DAX I can only get this to filter one of the columns (Either Originating Team or Resolving Team) based on a relationship. This removes a large number of cases that are related to their department.

How can I use USERPRINCIPALNAME to filter both team columns as an OR statement?

Thanks in advance