Exit Button - Not for controller 1

I’m wondering if it’s possible (maybe it’s easy and I’m just missing something) to map functions like “exit” to a different controller than 1. My arcade (Windows OS) has three different Generic USB Joystick/Button controllers, when I map the “exit” function to button 5, it automatically chooses the first controller, because I can’t use the same button to exit on controller 2. The first two controllers I have are meant for players, but the last is meant just for functions such as “exit”, “save”, “load” etc. I want to map those functions to the third controller but am not sure how, since the button numbers are the same and Retro Arch chooses controller one by default for system functions. I’m sorry if this is already answered somewhere, I googled for a few hours but couldn’t find an answer. Thank you in advance for any help!