In your teleporter gate blueprint you only need a volume. You an then reference that Gate in your Level blueprint, from that reference you can drag out a function called GetOverlappingActors. That function will give you the References to all Actors that are in that volume as an Array. Use the Get function to get that Actor and then you can use the Teleport function. Place the Second gate somewhere in the world, and reference it in the level blueprint. From the second gate get the world location (GetWorldLocaion function) and plug that into the Dest.Location in the Teleport function node.