Mastodon Groups have been implemented by third parties using auto-boosting accounts. Here is one example: search for @india (you must type their username into the search box: at India at gup.pe!) and follow them. The gulp.pe server creates the account when you search for it. If you mention it, it will boost your message, and thus everybody else following them will get their message.
If you are interested in a much longer blog post, see https://alexschroeder.ch/wiki/2019-09-26_Groups_on_Mastodon
@kensanata Oh wow this is really neat
@adasauce it’s hard to say since there is no overview. All I can say is that I haven’t seen much use of it. But it works for everybody, irrespective of clients, using standard activities like following and boosting. 😀
all I know is that the Russian speaking community has a bot that does that for them and it seems very active (not mentioning the lest it boosts this message, haha). This is the account from the outside:
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