Under Layer Settings, select the layer combination that has the wall layer you referred to turned off, then change the intersection group number (next to 'layer name' on the layer list) for the layer you want off to a different number.
Update the layer combination (bottom button on the left column in the center) and you should be all set.
When the intersection group numbers are the same they will clean up with each other, when they are different, they won't and you can change the numbers by layer combination.
hope that helps
-edit: just caught that you have AC9 so this may not work for you - anyone else know?
