Yes, Richard. Then it would work. It's always good to hear how others set things up. I learn so much from reading what members of the forum do.
In this case, what I find is the interior framed wall often needs to be a different height and stepped differently than the foundation wall to make sense for how it actually gets built. So, as I assume others may do, I keep them as separate walls, thus creating this problem. I have found a separate interior wall and opening aligned with openings in the foundation also helps me control the overall finish look.
I also prefer to have my foundation totally separate from the lower floor plans on 95% of my projects. So, I actually make any concrete foundation walls shown on the lower floor plan so they don't extract in 3D. It is a bit redundant when there are openings or changes to the layouts, but makes my model more the way I want it. My foundation is a separate drawing that I can model by itself if needed. I am really liking the ability to add steps, rakes, etc. to tops and bottoms of walls.