Group working on the same level in real time?

Is it possible to have a level act like a live server where everyone can can manipulate the level in real time?

Currently, no.

I’ve worked with Engines that do allow that, and it’s a nightmare (IMO). Code complexity goes through the roof, you lose atomic changes (so you can’t roll back revisions of a level), and everyone ends up setting up turns to modify the level anyway (to prevent stepping on each other’s work).