HELP house building materials wholesaler?

i urgently need a wholesaler for house building materials (drywall, doors, etc). Its for a project that consists of building 300 houses so homedepot or such are not the sellers im looking for. THANK YOU!HELP house building materials wholesaler?
All the sub division builders around this area get their supplies from local hardware stores...Rona/Home Hardware...at the back of the stores there is a contractor desk..this is where contractors will go to order their material receiving a discount once verified as legitimate. You can arrange material delivery as needed (you would not get enough for all the houses at once as this is not realistic). This is how contractors work around here from the small custom guy to the large builder.