add the ability to color code cross tables with nested headers

I have a cross table with 3 layers of headers and need to color row values per column. 

First Header Level:

in the example below if all 1a's were merged together that would be Customer

if all the 2a's were merged that would be Network

Second Header Level:

merge all 1b's = Past Due

merge all 1c's = Due Today

merge all 2b's = Past Due

merge all 2c's = Due Today

Please see attached file -- the 'Color by' is grayed out  and I can add no other items to the 'Color scheme groupings' section 

If I choose Avg Int or Count and pick a color the entire table gets that color.  Everything Customer and everything Network top to bottom. I have also attached a screen shot showing just that.