Ask HN: How can we create shared workspaces in Linux?

I am looking for opportunities to realise the following scenario:

I have three screens on my desk, and one of them I want to be a shared workspace with my colleagues. This means, we can easily drag application windows into it and discuss it across the network of Linux users. One common workspace for everyone.

Everyone gets their own cursor in the common workspace and can interact with it without any barriers, as if it were a workspace on their own machine, i.e. kind of what the Douglas Engelbart folks had at SRI.

I am pretty sure that some HN users here have some bright ideas that may help leap towards that vision.