When I used to make Counter strike source maps you could simply add a filter name to both the player and the object you wanted to trigger or collide with. So you could simply say “Only collide with objects with the same filter” or “Don’t collide with objects with the same filter”.
It seem’s in UE4 you can either tell an object it can only react to a single trigger (by exposing the trigger volume in code) or you use this crazy system! Which still has so many questions???
For example we’ve added OpenDoor which asks for a trigger volume but we only added it to the INSTANCE. What would happen if we made a class and dragged it into the world?
Furthermore what if we made a child of this class, would it still only accept input from the trigger volume?
My assumption is that the class won’t let you reference the gameobject trigger volume and that you will have to assign on run time.