Multibrand dealerships have been common everywhere I've lived - Tulsa, D.C., Houston, and now Knoxville. In almost all cases, it has depended on corporate ties, such as Ford's Ford-Lincoln-Mercury (still Ford/Lincoln here in Knoxville). Except for Cadillac's usually standalone dealerships, you'd find GM brands in multi-dealerships, with Opel squeezed in there somewhere in the old days. One of our largest dealerships now is Chrysler-Dodge-Jeep (Fiat and Alfa are separate). Mercedes sells Smart. BMW dealer sells Mini. Here, the same dealer has separate buildings side by side for VW, Jaguar+Porsche, Infiniti, Fiat+Alfa+Maserati. Then, there are the superdealers like Rick Hendrick and Rusty Wallace, who have dozens of dealerships in many different towns, selling just about everything. Many brands, like Mini and Fiat, require independent buildings dedicated to one brand, but that's subject to negotiation.