Assigning Gamepad / Keyboard to Player Controller

I’m making a game, and adding splitscreen, and I’d like the ability to go into a widget, and assign a certain gamepad to a certain player controller. This would be much easier to use, instead of plugging the controllers in a certain way, and making sure that everyone has the right position on the screen, and the right controller. If Player 3 wants to use the keyboard, they can simply assign the keyboard to their player controller, and now Player 3 is using the keyboard and mouse to play.