Hide row if column contains a duplicate value

Summary

Hide row if column contains a duplicate value in incident ref # column

Content

Hi all. We have a report used by numerous agents. The report has a drill down based on incident reference number. The problem is that the drilldown uses custom fields linked to the contact table; since the contact may have multiple custom table records the drill down report is showing multiple rows for the same incident.

What we need is to hide the rows where there is a duplication of the incident reference number. Hopefully the image below explains what we're trying to do. Any assistance gratefully accepted. TIA.