(Replying as @putty’s teammate)
Ideally the latter, but I realize the grouping of different users in different groups could be quite complex. The idea is that we have many internal teams at our company that are now looking to build experiences for their users on our Discourse, too. It feels sort of like we’ve built a parent community, but they’re also building mini communities within.
With this, many of them are interested in the ability to use the whisper feature in their group inboxes and categories. The issue of course, is that we don’t want them seeing administrative whispers.