Umg several controllers

So heres the question:
i managed to do this easily:

Now i want 2 to 4 controllers being able to only controll their on widget on the same screen.
Any suggestions how i confront this?
I am still testing out some methods.

trying to set is focusable to true, but now i want to limit a part of the umg to the 1 player, is that possible?

So the question is: How do i setup two different controllers to controll in one umg? And making them not being able to select certain images