If by “Hallway” you mean any circulation space, the Lobby tiles are what you are looking for, and they have special furniture to make the ground transparent so people can walk over space.
Note that any Lobby tile will draw tourists. If, like me, you don't want them to walk around your citizens' neighbourhoods (or worse, your slaves' quarters and training areas), don't use the Lobby tiles and the Window floor to make them look pretty. I did it at first and spent several minutes getting back to the plain grey tiles so those stupid tourists would stop trespassing in private areas. Too bad, I wanted my citizens to enjoy the scenery too...
By the way, this is something that could be added: doors. There could be the generic ones, that could be opened by everyone and used purely as a cosmetic addition (in the Lobby Furniture); ones that could be opened only by employees (slaves and citizens; available in the Apartments' furniture), and ones that could only be opened by slaves (available in the Slave Quarters' furniture). And maybe a Bunker Gate for the Military Base's furniture, to be as cosmetic as the Lobby door, but blocking everyone. This way, it would be possible to block even citizens from the Suite, or even the Slave Quarters, and to decorate the Apartments' areas without having tourists wandering in.
Which makes me think of something that could be easier to integrate: the Spa could become accessible to everyone and constitue an attraction in itself (but it would be possible to block any Spa space from tourists and/or citizens by using the Citizen or Slave doors)