Dear Sheilag
In Adagio, when you first create your data, you have the option for a 12 or 13 month Fiscal Calendar to accomodate what is considered typical accounting procedure. Within that structure, you also are prompted for the month and year in which your Fiscal Calendar starts - you are not limited to the January-December regular calendar year.
There is no provision to add more fiscal periods (months) to this standard structure (I would be surprised to learn that this functionality exists in any accounting product), although you can of course, keep a Fiscal Year open until you have posted all transactions before performing the Close Year & Change Fiscal Year functions.
I would suggest contacting either your Dealer or your Accountant for advice on the best way to handle your unique situation.
Regards