@mayel Please, please – update us 
These probably describe real things that people do. But some groups like to make up their own.
Oh, yes, forgot to mention: The things, I do are just to set a base.
Groups can make their own. We are really liking the approach which skohub does (see page or videos below) and we think that we can take it further.
If the group vocabulary itself is an ActivityPub Collection, the software would just either take this as a source for skohub (instead of a common git repo) or the software can just sync the Collection and the repo …
In another thread, I wrote:
The skohub.io people are powering a large portion of the infrastructure for german universities, e.g. the System where I find the books in uni libraries nearby, they know what they are doing - to learn about the benefits watch the short Demo Video or Conf Video …