Identifying multiple values within a range

[proGrav]

I have a question. In the attached excel file I have a list of customer IDs that come from certain strata. I want to use a list like this that is much longer
for conducting some survey research per an assigned quota, but can only survey one customer ID from each strata and in some cases, multiple customers belong to the same strata. Is there a quick way Excel could cross out or make it apparent somehow that once a customer ID has been used anywhere on the list just once, anything else from that same strata cannot be used?

[Leith Ross]

Hello proGrav,

Welcome to the Forum!

The attached workbook contains a macro which will fill the complete cells with "Not Available" after a "Y" has been entered for a strata. This should provide a good starting point for what you want to do. Let me know if this close to what you had in mind.