I need help with designing a report which uses a working day calendar instead of a normal calendar month.

i.e To show data for November, Crystal naturally pulls back dates 01/09/06 - 30/09/06

I would need to redefine every month where the 1st day is the 3rd working day of the previous month and 3 days before the end of the current month.

So November would = 27/10 - 27/11
December = 28/11 - 26/12 etc etc

Does anyone have any idea how I can do this or does anyone know where something similar to this has been done.

ANy help would be much appreciated.