Yes, you can create partial walls, also known as pony walls in two ways:

1. Drag a passthrough window (Objects -> Architectural -> Windows -> Pass Through) onto the wall and enlarge it so it takes the entire width and the appropriate height of the wall.

2. Use a custom box shape (Objects -> Architectural -> Shapes), flatten it to 4 inch, and stretch it to serve as the wall. Apply it with the same material as the rest of the walls in that room.