Is it possible for a trigger to only react to a single actor?

So essentially I’m creating a game where you have to get through a maze, but in order to complete the maze, you need to collect a “key” which is just an AI that follows you around. You then have to find the exit and bring the key into the sphere trigger. The problem is that the sphere trigger at the end of the level will move on to the next level even if you don’t have the “key”. I’m very new to UE4, with practically no experience and I have no idea where to start.

Make a variable in your character and set it to true when you collect the key. Then when you hit the trigger make a check to see if the variable is true and if so move to the next level.