It can be done with a homebrew campaign world if you set things out troupe style and allow each DM to add their own bits to the lore to surprise the others. You have to take a real "yes and" approach to shared worldbuilding tho.Yeah, a truly shared world maybe wouldn't be nearly as much fun for the DMs-as-players, in that much of the exploration piece would be made redundant - unless the world was hard-line segmented such that one DM gets this bit, one gets this, etc. but that kind of defeats the purpose of a shared world.