Since there haven't been any replies I thought I would try to explain what I'm aiming for.
I have several series - debit, credit, mortgage, wages and electricity. I want to have two bars for each day, one bar shows the stacked wages with debit shown as the "total" for the day. The other bar shows stacked mortgage and electricity and shows the credit as the "total" for the day. I will be giving users the ability to hide or show series and redraw the graph.
So far I can get everything stacked or everything grouped but with bugs on mouseover. Can anyone give me some pointers?