I don't think you can do what you want, although it's a nice question and a good challenge.
Could you create a front end to sort out what you want?
Or how about having several dynamic parameters and your static one and then depending on what you choose in your static one, your selection criteria could only use the appropriate dynamic one? The downside is that you would have to select some random value for each of the dynamic parameters or Crystal won't run.
Last edited by CasparV; 03-06-12 at 18:08.