I have requirements for a waterfall chart that I'm having trouble solving.
There's no problem removing the start and end columns, and this results in
columns that cross the X-axis. Jon Peltier's page on 'Waterfall Charts that
Cross the X Axis' was very helpful.

I've also looked at Jon's 'Fancy Waterfall Chart' page for
aggregating/stacking columns, but this isn't quite what I'm after. I have a
large number of Categories and wish to aggregate some of them arbitrarily
(ie, it needs a person to decide which to aggregate). Obviously only
negatives will be aggregated together, and likewise with positives.

A given column could have up to four stacked columns, and the difficulty is
in the calculation for each stacked column which could cross the X axis,
complicating the matter significantly. Has anyone already dealt with this
and have a solution?

Thanks in advance

Paul Martin
Melbourne, Australia