Six adults in one room would be a little cramped. I would be looking at either a 2 bdr DVC rental or a couple of value/mod rooms. I would not want to be sharing a single bathroom with that many people and not feeling like I had room to relax
Here are your options for 6 adults:
Family suites at All-Star Music
Family suites at Art of Animation
Cabins at Fort Wilderness Campground
Two and three bedroom villas at the deluxe villa resorts (DVC)
There may be some suites at the deluxes that will sleep 6, but I'm not up on the details.
Not against the rules -- against the law - the fire marshal sets the room capacity limit - if you violate that, you will not only be kicked off property with no refunds, you could get banned.Not only would it be very cramped, it would be against the rules. There are no single rooms that have enough sleeping surfaces for 6 adults.