I don't think so.

First of all, Hubzilla was born into the Fediverse. In fact, the term "Fediverse" was coined in 2012, the very year that Red, that fork of a Friendica fork, was re-written against the new Zot protocol and to what would become Hubzilla in 2015.

Also, Hubzilla was the first Fediverse server application to support ActivityPub, two months before Mastodon.

The last thing that any Hubzilla developer, be it Mike Macgirvin himself, be it Mario Vavti and Harald Eilertsen, would do is take over any technology from Mastodon.

Unlike Mastodon and somehow like Friendica and Lemmy, Hubzilla has always had two kinds of mentions. @ is for mentioning channels/accounts the normal way. @! is both for direct messages and for posting to Friendica/Hubzilla/(streams)/Forte groups (the quick way; there are one or two more elegant ways).

So normally, Hubzilla has three ways of starting threads in a group:

• posting directly to the group's wall
• sending a DM to the group with a special mention, similarly to Friendica (the reason why Friendica and its descendants use DMs as start posts in groups is so that only the group members see it, but your own contacts don't; also, this leaves you with a way to mention the group without the group reposting your message)
• restricting the audience of the post to only that group, using the permission settings below the post editor (similar to the above, but without the mention, using the permissions system instead)

The first way is out of question. Lemmy doesn't have a wall, and even if it did have one, it'd still require OpenWebAuth to recognise your Hubzilla login and let you post on the wall.

The third way is even more specifically Hubzilla. I'd be surprised if it worked with Friendica groups.

Another issue with the second and third way is that both result in either a DM or something that Fediverse software without a permission system understand as a DM. Lemmy communities, in stark contrast, expect public messages as start posts. I guess the devs wouldn't consider it wise for Lemmy communities to forward DMs to all their members. Even though this is literally what groups on Friendica and all its descendants have been doing since 2010.

Also, Lemmy doesn't know @!, but it does know what to do with the universal @. Mind you, neither Hubzilla nor Mastodon nor most of the rest of the Fediverse knows !. (Hubzilla was originally supposed to support both @ and ! like Lemmy plus an additional ! after either for "private", it even ended up in the user documentation, but it would have been overkill and utterly impractial to actually implement, seeing as Hubzilla forums need DMs to work anyway.)

And so the only way to start a new thread in a Lemmy community from Hubzilla is with a public post that all your contacts receive, and that mentions the Lemmy community with @.

On a sidenote: We've discovered today that it's entirely impossible to start threads in an Mbin magazine from Hubzilla. Mbin doesn't even accept @ mentions from Hubzilla.