Using a tablet to trigger an event


I’m stuck on a small blueprint problem and wondered if anyone can help please. In my first person game I’d like to use an android tablet as a 2nd controller for the player. On the tablet I’ll display a 2D UI button, and when the player presses it I’d like to change something in the level (open a door for example). How could I achieve that?

Would I have a second camera pointing at the UI plane, and output that to the tablet?