Link two picade consoles

Hi. I would like to know if it’s possible to link two picade consoles, in order to enable a second player.
I want the possibility for both my kids to play, each with his own console, but I want them to play together.
My question is:
One console has to be “master” (the one that connects to the TV) and the other is linked to this one just to provide the controls for the second player ?
Or both consoles can have its own raspberry pi, so each one can play solo, or multiplayer (when linked together) when they want to ?
Is this even possible ?

Thats a tall order. I’m not saying it can’t be done, or trying to put you off from trying it. I’m just thinking it won’t be all that easy. Not with my skill level anyway, lol.
I do want to tag along to see what others have to say though.

One way to “convert” a console into being a second game controller would be with this.

You replace the Picade Hat and Pi with the above. Then plug it into the first Picades USB port. I’m assuming the Picade software will let you setup a USB controller. The modified Picade won’t work stand alone though.
If I was going to do this, I would do it to this version

Thinking about this some more. If you also stuck a raspberry Pi in the modified console. You could then plug the Player X into it and play stand alone connected to a TV. Just swap around where the USB cable is plugged into depending on what mode you want, stand alone or second controller.
Maybe its not as hard as I was thinking?

If you are using retropie, you can use the netplay.