In some extends this is what the Movim project (https://movim.eu/) is building for several years now. A light solution that you can deploy on a server and that handle the communication of a small community (10 to a few hundreds people).

The good thing is that it relies on XMPP for all the communication, therefore all the instances are still connected to each others allowing communication between all the users of the network and with all the existing XMPP applications.

It offers social features (publications, blog, comments), chat (chatrooms, stickers...) and video-conferencing.

P.S. I'm one of the contributor of the project.