each object are different layer in both version (blender 2.7x & 2.78)

You can take the object that you need

by opening the "doors collection" scene and open the scene that needs it

then copy (Ctrl + C) then paste (Ctrl + V)

like most programs

Object is already parent for each door

Cycles and eevee may differ slightly in compositing e.g normal insinity

Let me know if you any question..