Reloaded will have an internal system for doors, windows and everything else as with previous versions of FPSC. I am afraid it will be best if you wait for the default system to be added to Reloaded so that both animations and the script language for managing entity animations is put in place. When it is you will I am sure easily be able to see how it works as at the moment we don't know how it will do so.
Neither animations nor the scripts required to manage such things are yet integrated. Only AI enemy characters have that at present and even then its hard coded into the engine at the moment with no real user intervention possible.
When the Indoors/internal room/building system is integrated then these things will I imagine be part of that.
Currently I don't think we know when that is likely to get integrated though.
The feature vote page may give you some idea of priority for that though anything can happen yet.