I'm working on a floor plan without many interior walls, but would like to separate certain areas and have them treated as unique rooms, so each can have it's own name, area, dimensions, flooring, etc. I am defining walls that don't actually exist between the areas, using wall thickness and height of 1/8". These "phantom" walls let me create separate rooms and don't show up on 3D renderings because they are so short and thin.

But this is a clumsy workaround that introduces problems when these phantom walls connect to "real" walls having normal height and thickness - the "real" walls take on the 1/8" high and 1/8" thick attributes of the phantom walls when they join up.

Any better way to get the program to treat different areas of one large space as separate rooms?

I have Home & Landscape Design Professional version 17.5.5.1001. I know that's pretty old but I'm keeping my fingers crossed. Thanks!