How do you keep categories split by color within treemap?

[pacificbeavs]

I created a treemap inside my dashboard.  It includes two categories (e.g. Region, County), and two measures (number of sales, cost of sales).  If I use one measure then the regions are split by color, however if I add the second measure then the regions no longer appear visually to be split, and instead the entire treemap takes on the heatmap type of shading. What was once four colors (one per region), is all different shades of blue. Is there a way to add borders between each region (by color), and still maintain the shading within the particular region?  Hopefully that makes sense!