By "pose" ... I mean, do you want to be able to move the wall(s) and have them stay connected to the rest of the room, i.e., floor?

You can do it with separate props for the walls and floor.

Import the object into Poser.
Use the Group Editor (Grouping Tool) to make a separate Group for each part of the room.
Now you can "Spawn Props" to have Poser create a separate prop for each Group (object).
Next, parent all the parts of the room to, say, the floor.
Save the floor prop and Select Subset and check all the parts of the room to be included.

Now you can load the room prop and then make each individual part visible or not.

cheers,
dr geep
;=]

Remember ... "With Poser, all things are possible, and poseable!"

cheers,

dr geep ... :o]

edited 10/5/2019