One great feature of Reporting Services is the ability to drill through to secondary reports. This is pretty straightforward to do, but the built-in option in Reporting Services is an all or nothing approach. Sometimes there is a need to drill through to secondary reports based on certain data conditions, but you do not want a link for every row only certain ones. How can you provide a link for some data records but not others?
The solution is to use if IIF() function within the report navigation expression window.
The article continues at