Thanks Roelf, but what I need is actually a bit more complicated than what I first described (now that I have a full understanding of what our corporate controller wants).
What we have:
A database with all transactions that store info from about the middle of 2002 until current.
What we need:
A database that stores only info from 9/1/06 until current and a second database with only info from mid-2002 until 8/31/06.
We have about a million tables, relationships, etc. (slight exaggeration) to actually go through the tables and split them by a certain transaction date (and find out which dependent tables were affected by this), esp. transactions that were posted post-9/1/06, but affect the previous month. I called Microsoft to see if Great Plains has any capabilities to remove history, and let's just say that it's not very friendly and agreeable. Since the year isn't closed, we attempted (using MS's advice) to change the fiscal year end to 8/31/06, close out the year, and then remove the history for that year. Let's just say that good thing it was a test copy.
The accounting department is doing it their own way, so I've sort of backed out of this project. So I'll just leave it at that. Thanks for your help Roelf.