@cyberic Seems to work. You have to follow the Lemmy communities from Mastodon in order to be able to add them to a list, though, and the list only populates with future posts to those communities, but those are the current lists restrictions on Mastodon, and I believe that lists of fediverse accounts that you don't follow are in the making. (I'm trying lists for the very first time. They are obviously server-based, and it‘s interesting how they manifest in the different apps.)

@cyberic I've never tried lists, but can't you just make a list on Mastodon of those Lemmy communities that you want to see in a single feed?