It's actually very simple.
Connect an hdmi from each receiver's output (the main one if it has two) to an input on the TV. When you want to view the menu for that receiver, select the TV hdmi input it is connected to.
It occurred to me that sometimes you can't select an hdmi input that's not...
Just to add, the Yamaha is a current model, and should have an on-screen menu, but the Integra is from an era when they often didn't. You don't say which one you can view on the TV.