[Therion] Coloring on a altitude basis

Hello, I searched in the archives and I didn't find an answer. I like to make plan and extended sections colored by altitude because this is a way to add a "3rd dimension" to a plan drawing. I also like to have the same color in the same cave region either in plan and extended section. This way makes very easy to identify same portions of a cave in both projections. Because Therion colors on scrap basis, I'm forced to draw plan and extended section using the same scrap subdivision. This is a very complex operation and it's not always simple to have the same scrap structure in both projections. Is there a way or a trick to color by altitude, maybe defining an "altitude step" to change colors? Thanks, Marco