Co-op drawing on a project

I think very difficult to do but it would be very VERY cool if the team add a feature that allow 2 or more users to draw in “live” on the same project, using steam’s friends feature, Maybe with more cursors on screen with different colors that show where the other user is.

How would this work for non-Steam versions of the program? Or Steam versions where the user isn’t signed into Steam Friends?

It’s an idea obviously.