hello!

I have a bubble chart which I'm trying to add lines (or coloured squares)
to, so I can group the bubbles into 4 defined-by-cell-value parts of the chart

Currently I have 2 lines crossing the chart which I have to manually move if
values change (they should each cross the axis at the weighted average point)
but as the chart is going to be made into multiple versions I want to
automate as much as possible

I did see Mr Peltier's guide for adding dynamic quadrants to x-y charts (I
don't mind if the bubbles are segmented by rectangles either!) but couldn't
find anything showing me how to do it with bubbles - any ideas?

using XL 2003

Many thanks in advance for any assistance!