The easiest would be exporting open and close door in one .X file.
Then you can use the command
play object id, start, end to either open or close the door. (ie. 1 -> 20 = open door, 20 -> 40 = close door)
You can close the door or set the door open without having animation by using
set object frame id, frame, which will instantly change the current frame number of the object.
If you want to save the animation separately from the file, you can try using DBC's own animation commands.
I hope it helped.
Sven B
It's the programmer's life:
Have a problem, solve the problem, and have a new problem to solve.