The GD::Graph doc shows how to cumulate more than one dataset into a single column in a barchart by setting

cumulate => 1

But, I have 4 datasets say, A, B, C, D. I want datasets A and B cumulated (stacked on top of each other). Similarly, datasets C and D cumulated as well. The two stacked columns should appear next to each other. In other words, each X-axis value will have 2 columns, each column representing two datasets.

Is this possible using GD:Graph? If not, is there a workaround to get this done?

Thanks!