Drill-through help needed

I have a bar chart which shows the value on a group of AP Balance sheets. This is made up of 3 balance sheets that feed into it. What I want is to be able to drill-through from the overall number to then see the breakdown of how much is on each balance sheet, but I have been running into issues with this. Hierarchies don't work as the 3 child balance sheets are equal and are not a child of one another, and can't all sit at an equal level below the parent balance sheet.

Any ideas?