Modifying internal wall groups?

I have a 2x4 timber exterior wall that is 8’ high, but has a brick veneer on the outside that only goes up 3’. Is it ok for me to choose the Brick veneer wall type, then open the group and edit the height of the brick veneer manually? Will the takeoff still track the volume of bricks needed for the takeoff? Will I lose my manual edits once I add a window or door?

Nevermind, I realized I can use the “Manual Override”, to give the brick a “Drop off” to the dimension I want. Now the problem is how do I get the upper part of the wall to include siding, and the lower part of the wall not to include siding?