Hello modcraft community !

I have a little question for you guys about the Modelling for World of Warcraft. Recently I had the idea to create some custom habitations for 3dsMax in order to integrate them into  Wow, however, according to a reliable source, it is impossible (or very difficult) to convert my model into a WMO.  
M2 format seems appropriate then, however, I have some misgivings about the M2. It does not seem that objects of type M2 can have an interior, but an interiror for the house over which I am working is needed.
My fears are well-founded ?
If so, is it possible to create models such as:
-The house (exterior) and interior separately ? The interior would then not acessible via a door but through a system whose function is to move the player towards the inside of the house.
Do you think it could also work or are you skeptical too ?

Hope I've been clear enough, thanks in advance and have a good day !
Regards,
Eliphas.