Want to find and display only duplicates

[elmo416]

I am using FM 6.0 to sort research data. The data involves what strategies various students have used for different questions. Each student as a unique student code. IT is also a multi-user file. What I'd like to do is to pull up students who have used the same strategy on different questions. For example, I only want students who have used strategy A on Questions 1 and 2. When I do a Find, I get students who used strategy A on question 1 or question 2. I only want the students who used it on both. I think what I want to do is to find the duplicate student codes for the found set mentioned above, but I am not sure how to do it. Any help would be greatly appreciated. Thank you.