Actually, I don’t make any efforts to make it compatible with existing microblogging software. And it indeed isn’t, because it relies heavily on walls. Those that I wrote a FEP about.
Mastodon does show a “group” tag next to it, and you can join it (I recognize both Join and Follow), and that’s about it. You can’t interact with it because that requires sending activities that Mastodon knows nothing about.
And, IMO, that’s fine. You can’t exactly reconcile all the problems that arise when you try to interoperate disparate software. People usually understand that. You can’t make a microblogging server participate in a forum network without it all looking ugly to the user on the microblogging side and to the developer on the forum side. I’m very much against perpetuating such legacy workarounds, like “mention this account and it boosts”, to make conceptually incompatible systems compatible at the expense of UX.