dual hitch receivers/storage

The Roadmaster pictured above has the largest load rating I have seen for these hitches. I also use this hitch for towing my toad (bottom receiver) and carrying a cargo platform (upper receiver). I can carry the cargo platform or my bike rack in the upper receiver without a problem.

I have never noticed any interference between the rack or platform and my toad. I actually have an older tow bar (Roadmaster Stowmaster 5000) with a ball socket, and have a ball hitch in the bottom receiver.