Quote Originally Posted by bust3dstr8 View Post
You can't just split both wires and then connect to button 3.
That would short the two for button 1 and 2 also, giving you a double button push for all the buttons.

You would need to isolate the inputs with two AND logic gates.
Depending on how the inputs behave you may have to add pull-up resistors to the inputs as well.
Ah that's right, didn't think about that at first.