I have a crystal report that shows student registered courses and the credits.
Then for each student ID group footer, I have a running total field to count the total credits of the student, called totalcredits

I want to add this total credits field as a parameter too, so that when users run it, it will prompt for example the user enter count>5 etc.

But I cannot find a way to create a parameter using the running total field,

How can I do it?

In the create new parameter screen, for list of values, I can see all the fields, but the total running field is not listed there.

Help please.