Button troubles: over keyframe

A simple rundown of what I want.

I have 2 buttons. Button A is a square, that when Button A is hovered over, the square turns blue.

Now I have Button B. Button B is the text “BLUE”.

How do I get it so that when Button B is hovered over, it plays the OVER keyframe of Button A. And vice versa.

Basically giving the user 2 ways to changing the squares button.

Thanks,
Brett