How to build a door shared by two jamb openings
It can be done fairly easily, with normal hinges too. It would take a bit of alternative framing and jamb work.
Open any normal &quot;in swinging&quot; door 90° and look at the gap between the door and jamb on the hinge side. This is what you have to hide. If you look at the pictures you will see that the door on the right is hung in a normal fashion with traditional jamb configuration. The other door has framing and jamb work that is &quot;built out&quot; away from the wall; the hinges end up buried on that side and the gap is eliminated.
One challenge is that a normal lockset will not work (note in picture there is no lockset installed). You would need an alternative style of catch that works in both directions, such as a large bullet catch (see below), and some method of ensuring privacy (like a flush bolt, surface bolt, or old-school hook &amp; eye).

You may be restricted on the types of privacy device you use (especially for rentals or public bulding) as normally a method of emergency &quot;unlatching&quot; is required, in case someone inside has a medical emergency or what have you.