Here in BOM, I have never had drivers who have insisted that we have to sit in separate cars. We typically sit together as a family (3 pax) in 1 car and most of our luggage goes into the other. A couple of times we have spoken to the car company (Hertz previously) for EK pickups, and they have gladly provided 1 car and a separate "luggage van" which was a Toyota Innova.