I would like to change the exterior look of segments of the exterior of the house. For example, I am planning a rock look on one face. I also have an exterior wall with cedar siding. However, every time I select the single wall section and try to change the materials, it changes the look of the whole house exterior. If I change wall covering, it is on the interior. See the photo. You can see the cedar wall at the entrance. What do you suggest?