Please find attached a sample project that demonstrates how to hide an item (TextBox) with duplicated values. Although, Telerik Reporting does not provide this functionality out-of-the-box there is a workaround that we consider good enough. We encourage you to give it a try and if you have any question, please do not hesitate to write us back.
As far as this functionality is widely exploited we will definitely add it to the Telerik Reporting feature set in the future versions.
the Telerik team