I don't think so, but there may be a way.

Mastodon has the idea of 'Groups' (which are Kbin Magazines and Lemmy Communities), but it seems to not have methods of creating one. While you can subscribe to hashtags in Mastodon, I don't think they are equivalent.

Groups/Communities seem to be a non-native concept for Mastodon, but it seem to treat it as a person (from the short time I subscribed to a lemmy group/community from mastodon, it seems you get an update for every comment or reply made to any topic)

The idea of following a person (or subscribing to them) seems to be a non-native concept in Lemmy and there doesn't seem to be any way to support it.