It seems like the right way to charge a fleet of vehicles if your site has limited power is to have some central device that coordinates charging rates, so that

It seems like the right way to charge a fleet of vehicles if your site has limited power is to have some central device that coordinates charging rates, so that together they only pull as much current as is available. You could also set priorities. That way you can install as many charge ports as you want, and just have to worry about whether you have enough power to charge all your vehicles every day. I don't know if that sort of setup is commonly done or is allowed by code.