Mirror player 1 and player 2 controls on x-arcade tankstick?

[jdoc]

Hi everyone: Some classic arcade games like Donkey Kong and Defender have a 2-player option, but only required one control. This is reflected in the retropie emulator as well- only one control is needed to play either 1 or 2-player games (i.e., the player 1 control). The player 2 control in these games is completely inactive. I'd like to activate the player 2 control for just certain games within the rom (games like Street Fighter use both controls but for different players at the same time).

My setup:
-Raspberry Pi 4
-Retropie 4.7.1
-X-arcade Tankstick 2(2 controllers and a trackball)

I've searched the forums and found a few posts which linked to videos, but the videos are no longer active. I've watched the videos included within the Retroarch section, but not helpful for what I want to do. From what I can tell, I need to 'mirror' the controls- make the system believe that both controllers are acting as player 1. Any suggestions?

Thanks.

[LeatherWing]

@jdoc If you're running mame for these games hitting Tab should pull up a menu.
I'm positive you can remap the controls for individual or all games and save from there.

[mitu]

If you're using a RetroArch based emulator core (e.g. FBneo doesn't have an input menu similar to MAME), then you may be able to do that using the 'Mapped Port' option in the core input, see https://github.com/libretro/RetroArch/pull/12534.
I haven't used it, so I don't know if it's possible to save a game input remap after setting up this options (so it will configuration will be automatically applied when the game starts).