Subreddits have sister and subcategory subreddits on the sidebars sometimes. In some cases it was organised by a higher level subreddit, but it doesn't have to be that organised. Just mentioning relationships that are worth people's time is enough for many.
It wouldn't be that hard to do the same here. It just depends on the moderators style. Usually a team of 4 or more active mods is enough to make things appear in a progressing forum.