search for: pivotcharts

Hello, I was wondering if anyone knows of a way to produce multilevel x-axis groupings similar to Excel's pivotcharts. (If you're not sure what I'm talking about, here's an example: http://peltiertech.com/WordPress/chart-with-a-dual-category-axis/). I realize that I could use mtext to manually insert text where desired, but I was hoping for a more systematic approach. Thanks in advance, -eric [[a...