title: Dynamically change parameters based on the value of another parameter?
body: <p>I have a crystal 2008 report that allows users to group to two levels.
  I have two parameters, using which users can select which attribute they want to group on. 
  The two params are of type string and the list of values is static. Both levels have the same options to group on.</p>
  
  <p>Is there someway to filter the list based on what they selected for param 1. So that they cannot group on the same thing twice.</p>