So I am trying to add a button on my Game Boy that will "press" A+B+SELECT+START at the same time. I have found the test points for these buttons on the PCB and connected them to a button with the other end to ground, tested it and it worked just as I expected. But then I tried to press B by itself and all the buttons are pressed again, makes sense seeing how all the test points are now connected on one end of the button.
Do they have buttons that are 5 inputs that are not connected until the button is pressed, or is there a way easier way to do this that I am not thinking of?