Excel Region Based Heatmap

Hi everyone,

I am trying to format a 3D Map within MS Excel. For example, we have a region with one color and we want the color of the counties in the region to graduate based on the volume. Ideally, each region would have a color and the shading would darken based on county volume. What I'm trying to do is have the color of the county within each region to be shaded based on volume in that specific county, not region. I'm trying to get the heat map to shade each based on volume within the region. Certain Regions have 1 county, others have 15.

Attached I've included a sample of the data as well as a screenshot of the map that I currently have. What I'd like is for the map to shade based on the county specific volume compared to the region as a whole. Currently, the color coding is based on region which I want to remain, just add shading.