If you have 'fake/dummy' groups, they will use the display name from the highest possible group inheritance (when there is no display name set) or you can just use the same display name multiple times.

Example:

Group A:
  display name: Owner
  weight: 100
  parents: none
Group B:
  display name: none
  weight: 99
  parents: a

Now people with only group B will display the displayname of group A, which is Owner in this example.

I don't understand what you're trying to suggest

I've added an example.

Display names aren't inherited

That's exactly why I made this suggestion. Make display names inherit. 😃

That doesn't seem like a good idea. Group names are meant to be unique.

I see your point.