Copy wall textures to ruined walls

There are only a limited number of 'ruined walls' available. It would be great if you could 'paint' the texture of a wall type onto the ruined walls, rather than having them with set colours. That way I could set my dungeon to look one way, stick some ruined walls into certain locations, and then paint over them for the same feel throughout. Would be a bit like the generic 'green screen' shapes, just with ruined walls in their stead.