How to connect two dungeons?

[deal5]

Hi! I need help.

I need to connect two dungeons but in Creation Kit only one .esp can be active, so

each time trying to use teleport option for door in active file and choose reference in second one

i'm just getting duplicated cell which contain only door with marker.

I don't understand how to save changes for both files? Or i should recreate second dungeon in duplicated cell?

I've found this link from pinned topic but i'm not sure will it help me.

Thank in advance for any help.