First an example of the data I am working with:

Account# Customer Date Invoice Totals

235 Joe Jan 07 $100.00
235 Joe Jan 07 $150.00
824 Sally Jan 07 $350.00
235 Joe Feb 07 $75.00
824 Sally Mar 07 $200.00
824 Sally Mar 07 $100.00
235 Joe Mar 07 $150.00


I am need a formula that will add the Invoice totals for each row where the
Account# is equal and group together by month. The criteria will be from a
different worksheet within the same workbook so the end result would
hopefully look something like this:

Account# Customer Date Invoice Totals

235 Joe Jan 07 $250.00
Feb 07 $75.00
Mar 07 $150.00
824 Sally Jan 07 $350.00
Mar 07 $250.00

I hope this is possible and appreciate any help that will get me going in
the right direction.

Thanks ahead of time,

Mike Koop