In BIRT, how can I filter a crosstab by List groups?

Question

I'm working with a data set that has a main category and a subcategory, and within each subcategory, I want to display a crosstab of the data within. I'm coming from Crystal, and the crystal equivalent would be creating two group levels (1 and 2), then creating a crosstab in the group 2 header or footer. The result is that there would be a separate crosstab that would display for each subgroup (group #2), and each of these crosstabs would contains only the rows and columns from that subgroup, as well as of course only the summary data for that subgroup.

I see in BIRT I can add a List, which seems to function like groups in Crystal, but when I place a crosstab into the list, the crosstab does repeat for each group, but each instance contains the entire data set. How can I make it so that the crosstabs are essentially filtered by the groups they appear in?