There are times when a door (or window, opening, or door/window assembly) gets placed into a wall that has another wall (or multiple walls) adjacent to it. Even though a door can be placed in only one wall, it is possible to create an opening in the adjacent wall(s) so that when the door is relocated or changes size, the opening in the other wall(s) change accordingly.
Place the Door object in the desired wall.
Highlight the wall(s) adjacent to the wall with the door, right-click, and select Interference Condition, then Add from the pop-up menu (as shown below).
When prompted to Select AEC objects to add:, pick the desired door (or other allowable object) and press the ENTER key.
When prompted to Enter shrinkwrap plan effect [Additive/Subtractive/Ignore]:, type S for Subtractive.
(Subtractive will subtract information from the adjacent wall, and Additive will add information to the adjacent wall.)
If there is a gap between the walls, and you are prompted with Object(s) that do not touch the selected wall were detected. Still apply interference? [Yes/No] <No>:, type Y for Yes.
You now have one door that affects 2 different walls.
Applying Technology to Architecture 
Hello Doug,
this is very nice feature! I found it some time before but I have problems with it. Do you experience the problems of incorect plan representation (in plan not cutting the wall, or cuts only some part of it)? The problems I have was when you have thin walls which have to cut. If the wall is too thin this function cuts the opening (in 3D) but not represent it in 2D plan). How thin should be the second wall for displaying this problems depends on how much is the width of the wall were is hosted the Door. Thank you a lot.
Radoslav Stefanov