I think we'd want "Jitsi Meet" rather than regular Jitsi (which is a sip client). I checked into it for a minute and it seems like a possibility, though the server side is a big Java program and it's not real clear what its release status is. It's not officially announced as released software and instead there are downloadable snapshots. But inside it says LGPL 2.1 license. I'll look into it some more.
RMS also referred me to a lady in Canada who I've emailed but not heard anything from, and I'll make some other inquiries. There really should be a usable solution for this.