Hotkey Combination to bring up MAME (TAB) Menu in-game

[Rick]

Hey all, I'm having a bit of trouble.

I use RetroPie on my arcade cabinet, and have my hotkey set to "SELECT". RetroPie allows you to press "SELECT" and "X" in-game to bring up the RetroPie menu.

What I would like to do is assign "SELECT" and "Y" to bind to the "TAB" key, so that this combination will bring up the MAME menu in-game. I cannot determine how to do this.

What DOES work is going into the MAME menu by pressing TAB on my connected keyboard, going to  "Input (general)", pressing ENTER to edit the "Config Menu" option, and pressing two buttons such as Player 1's "Y" and Player 2's "Y" button simultaneously. Unfortunately, I cannot use this as a solution, as there are many times when both buttons could be pressed at the same time, especially in a fighting game.

If I do the same process, but try to press "SELECT" and "Y" together to update the option, my arcade does not register "SELECT" and "Y" together. When I try other options such as "START" and "Y", it also does not work.

I went so far as to build a script to convert the simultaneous input of "SELECT" and "Y" buttons to enter "TAB", and while the script works when I enter an editor (such as NANO), it does not work while Emulation Station is running. (It may be that I just need a different approach, but I am still trying to see if this might work as I do have a current script that converts my power button input to a shutdown script, and that functions properly.)

Is there a simple solution that exists that I am overlooking? I would prefer to not have to keep a keyboard handy, if I can help it.

Thanks, in advance!