If I have two parallel walls, how do I make them some exact distance away (e.g. 4 feet 2.75 inches) from each other?

In visio, there is a tool that can be attached to both walls, then a distance can be typed into the tool to push/pull the walls to that exact distance. I don't see a similar tool in sweet home 3d. The only way I see is to use "modify wall" and enter coordinates for the walls.

What happens if instead of two walls, I want to adjust the distance between two rooms I already drew? There seems to be no way to enter coordinates for a room. I can drag the rooms to an approximate distance apart but how do I get it to be exact?