Local follow
tl;dr
A federated category could follow a local federated tag.
Use case
I have a category that relays all Fediverse accounts from my organization in a single place.
Now, I have this incoming message from the Fediverse that announces an event related to an existing (non-federated) category. So I’m moving that topic to the expected category and add a few relevant tags, including #fediverse.
The #fediverse tag is an ActivityPub actor that I use in addition to the federated category so that I can share a specific topic with the Fediverse from anywhere (public) in the forum.
Issue
Currently, the federated category won’t follow a local tag.
Expectation
I would like to be able to follow a local tag actor from a local category actor, so that it appears in one place on the Fediverse.
I.e., if @fediverse@discourse.example is the category actor, and @fediverse-tag@discourse.example is the tag actor, I would like that accounts following the former also receive the latter, without them having to discover it.
Discussion
Probably that requires a bit of thought since it would be impractical that the forum duplicates the discussion: is it possible to stick the discussion to a single place (tag trumps category) while delivering it to the category followers (category trumps tag)?