I have data validation set on cell A1 so that it has to be populated from a list.

Cell B1 = A1

I would like to set data validation on B1 so that an error alert appears if B1 = 6

Is this possible. I presume an alert cannot be set to A1 because it already has a data validation rul set. But the alert on B1 is only activated if 6 is input into it directly (not via change made to A1).

Any ideas anyone?

Thanks in advance