for a simple door, the frame needs nothing doing, then select door and set its parent to the frame, then open joint editor and set the origin start point to the door edge(where it meets frame)(start point is green end point is red) for a simple door the end point can be in same place as start point but for something like a bi-fold door then the end point needs to be on the start point of second door. Door should rotate corectly with y rotate, some times you may have to change the rotation order (top right of joint editor)

hope thats a help an not something you already knew ;-), this method is ok for about 3 maybe 4 joints, more then that an it gets hard to use easily there is 2 plugins I know for poser (easypose underground and all tied up) but dont know if they work with DS or you could read up on ERC,IK and FK is quite a few tuts on that