Filter Email Notifications by Topic?

Hello there :wave:

I’m struggling to find the right option here, but guessing it exists… we have several topics (categories) and users who which to subscribe to just a single one, so they get Email notifications just for that topic.

I can’t see how that’s done. I can set to Watch all threads in a topic, but not tie that into the email settings. :thinking:

Is this possible? Can you point me in the right direction?
Thanks.

(Relatedly I was looking for an RSS feed for a filter is that feasible too? Two-for-one, thanks! :smiley:)