GroupWorld.net is a secure, customizable, cross-platform web conferencing/meeting software package which allows you to set up online meeting rooms with whiteboard, voice/video conferencing and desktop sharing.
"The world's best video conferences are built on Jitsi.
Jitsi is a set of open-source projects that allows you to easily build and deploy secure video conferencing solutions. At the heart of Jitsi are Jitsi Videobridge and Jitsi Meet, which let you have conferences on the internet, while other projects in the community enable other features such as audio, dial-in, recording, and simulcasting."
"Matrix is an open standard for interoperable, decentralised, real-time communication over IP. It can be used to power Instant Messaging, VoIP/WebRTC signalling, Internet of Things communication - or anywhere you need a standard HTTP API for publishing and subscribing to data whilst tracking the conversation history."