I was recently introduced to the Houseparty app, which is free; this app solves the problem of scalability; up to eight people can enter a 'room' to chat, but any number of those you invite as friends can be online; it is phone based, not pc based. Any number of 'rooms' can be created. A room can be 'locked' for a private session.
You can find a list of the first users to sign up at https://www.patreon.com/posts/convivium-9438967:
To get you started, some usernames are: draconigenus , classicalrevival, cragius ,felixmusicus,
lvpvs , molendinarius , mrbrugger, occitanus ,sermohumilis ,stolidior
You can also add me (molendinarius) by direct link: http://go.joinhouse.party/CcEg/zEqkHEQnHC
It will be interesting to see how this develops,but so far, things are panning out well; it is working far more effectively than any previous video-chat interface.