I think the answer is no, unfortunately. Here's my use case:
I have a course hundreds of people are taking every year, each for different reasons, usually because I or someone in my agency requires the completion. Usually the only groups are internal for me (or the people who requires those people to complete).
For example: anyone who works on project A has to complete. Anyone certified in project B has to complete. Completers in Project A and Project B can work for the same school district, university or company, so you might be in Group A and Group B or just A or B.
But things have changed.
Now, some of our school districts are requiring all their staff to complete this course and would like a way to see their staff have completed outside of asking me (which is a rabbit hole I would also prefer to avoid). Easy, I add all of them to a new group (call it group C) and give someone non-editing teacher permission (tech director/superintendent, etc). Except sometimes that person also completes because they are a member of Group A or B. The new permission allows them to see everyone in their district group AND the other group(s) they are part of. Which is no bueno. Is there a way to assign a permission in the group not in the course? or a way to link the group to the permission? I think there isn't but I'm hoping someone has found a workaround.
The only solution I can think of is to assign groupings (can you filter activities/completions by groupings?) but for this case, it would be super manual and I don't love that.