Except for a couple express GPO's most non-national GPOs are nearby. A group of organizations in a city in a specific industry get together and structure a GPO. The point of preference is that every part has say in the sellers that are chosen by the GPO. The other point of interest is that the GPO is free. The issue is that a couple of dozen individuals from a neighborhood GPO don't have the purchasing energy to get huge rebates from merchants.