I'm not aware of any 1.25 receiver bike racks that will hold 4 bikes (although that doesn't mean they exist).
I would recommend the tray type bike racks if you can find one that fits. More secure, works with various types of frames and wheel sized -- mine fits my downhill bike with a crazy frame to my road bike to my kids' 20" wheel bikes.
There is always the trunk-mounted racks if you cannot find a receiver that will work. Or a roof rack - you should be able to fit 4 bikes on top of the car if you get the right setup.
As a mountain biker and road cyclist, I know it can be tough to find a solution. Good luck!