Counting like records only once

[NelsonFMP]

I have a solution that tracks client visits so there are multiple client records (the same client ID). In a report format I need to be able to list the clients only once, which I can do with a sub summary part, but I also need to be able to count the clients and only count like clients once.

Example: I have 5 clients with ID 1234, 5 with ID 1111, 2 with 1212 and 1 with 4444. With them all listed in a report sub summary I only see them once, but the count and summary count all occurrences of all clients. Using a count and count summary field I get 13 and I want 4. Any ideas how to do that?

[comment]

See if this helps:

http://fmforums.com/forum/showpost.php?post/297916/