I have the following example data:

Month1 / Qty 1 / Qty 2 / Qty 3 / Qty 4 / Field A
Month 2 / Qty 1 / Qty 2 / Qty 3 / Qty 4 / Field A
Month3/ Qty 1 / Qty 2 / Qty 3 / Qty 4 / Field A
Month 4 / Qty 1 / Qty 2 / Qty 3 / Qty 4 / Field A

The user can select a quarter "start month." I need to set "Field A" to a
unique variable for all months that fall in the quarter.

So, if Month 1 is the Quarter start month, Field A would read "x" for Month
1, Month 2 and month 3.

If Month 2 is the Quarter Start month, Field A would read "x" for Month 2,
Month 3 and Month 4.

I currently am using a public function, but it errors out a lot when people
have more than one excel file open at a time.

Any assistance would be greatly appreciated.

Thanks,

MTinsley