applying material to only one side of cube mesh

So, I’m kind’ve a big noob with UE4, and I’m making a level with the starter content meshes. I would like to make a wall for a room, and have the interior be a basic wall texture, and the outside be brick. But if I use the wall meshes in the starter content, it applies the mesh to the whole wall, all 6 sides, and not just the wall I want.

This is probably very easy and I’m just overlooking something, but is there a way to apply a material to only parts of a mesh??