I mean, if you have a masto account, like on mastodon.social or lgbtqia.space or wherever, you can post from that account to any community on the threadiverse (lemmy, piefed, mbin) by mentioning it in your post. So, for instance, you could include at-nwsl-at-lemmy.world (using the @ character instead of at-) in a mastodon post, and the resulting post would remain on your mastodon timeline, even if I moderated it from my NWSL community. If you want to see examples, a lot of the serious fediverse knowers post like this to !fediverse@fedia.io