Sorry. First of all is my idea even possible to accomplish?
And if someone is able to do this i'd be glad , and i think other ppl too.

I have had always idea of making own interior to map.

How could it be done?
Open All Interiors v4 by NewTheft
Like he uses in hes mod teleports to interiors. That could be modified i guess? And in fact with mod Map Editor 2.13 you can build in out of map. I have no coding skill at all. If someone is able to do this teleportation (or some sort of) it would be amazing!

-Jehowa2 (The guy who's comma doesn't work)