Is there a database design pattern name for reducing duplicate join table data?

I have two tables with a join table to allow a many-to-many relationship.

It's a very familiar design pattern. It indicates which Branches each Member has access to.

As the number of members and branches increases I end up with a lot of data in the join table that is duplicated across members. Members tend to have access to the same groups of Branches as other Members.

So I'm looking at normalizing my data by creating a MemberProfile table that is effectively immutable. And rather than creating MemberBranch records for every Member I check for a matching MemberProfile, use if it already exists, or create one if it doesn't:

The idea being if I have a million Members with only a hundred access profiles this will save me a lot of space in my database.

I'm happy that it all works and that the development effort is worth is.

My question is "Is this a standard database design pattern, and if so, what is it called?"