Maybe everybody is busy, being week-end and all. As an update to my problem, it seems like Channels are the way to go. I see even here on Una.io Groups and Spaces are not used, but Channels are. If I'm posting a discussion, an image or a Video and add a hashtag to them, the content is present on every section, including on the Channel itsefl.

The problem now is that Channels don't have members to them, just followers. I wanted to have members like on subreddits.