Probably the neatest way to do this would be to sign a contract with a specialist contract to construct the main roads, utilities, infrastructure and boundaries with each homebuilder being individually responsible for obtaining PP for their own plot and proceeding to construction with their own design. Sounds like a good idea in principle but I think that unless the group of people have a very clear common goal such an idea will never get beyond the paper stage. It's a bit like these "dream paradise island" communities who think they share a common vision, but once human nature comes into the equation the whole thing falls apart.