What I did, was put marker actors in the levels at the connector points. I wrote a bit of BP, to save those actor transforms to the save game.
Now my levels always line up, because a vector calculation can be used to figure out how to connect those marker points together.
That’s the most general case. If your case is simpler, you might be able to get away with a simpler concept. It might be enough to say ‘room size + rotation’.
If you’re interested, I can put the code up here…