How to enable voice chat between sessions

I have a web app (game) which can allow up to 4 persons to play inside a single “game” (but potentially my app could host many such games concurrently). I would like to add a voice chat feature, so that, for example, the 4 persons playing a game (say, game ID:001) could all talk to each other (regardless of their individual browser / device / platform).

I believe there are a number of open-source audio chat client / server solutions out there, such as Discord & Mumble, etc - and does anyone have any experience with this kind of thing, and how it could be integrated into a Xojo webapp. (and I could host the audio server on the same server as the app, perhaps.)