I need to put in a data validation for column b (distributor #) based on what is entered into columns a (location) and c (product #). So, if I enter Texas into column a and enter either product # 369 or a 698 into column c, then I don't want a distributor number to be entered into column b - I want a flag to come up if someone tries to enter anything in column b, but want them to be able to enter a distributor # in there if Texas isn't entered into column a.

One additional issue is that the order in which the spreadsheet is filled in. Normally people fill in the columns from left to right. I cannot change the order of the spreadsheet due to it being an upload template. So, Column b will usually get filled in before column c. Is there a way that the data validation will still work if product number 369 or 698 is entered into column c after column b has already had a distributor number entered into it?

Thanks for you help!: