So i am trying to show only one Payor for a service a client received.  Most clients have more than 1 payor, and some payors may be expired.  Here is my example:

ClientID   Service   Service Date  Payor
1              IZ HPV   6/02/11         Blue Cross      
1              IZ HPV   6/02/11         FPEP
1              IZ HPV   6/02/11         No Effective Payor

So basically at the service date the client had 3 payors but only 2 of them were effective (Blue Cross and FPEP).  I only want to show one effective payor, or if all three were not effective and shown as "No Effective Payor", i want it to only show "No Effective Payor" once.

like this:
ClientID   Service   Service Date  Payor
1              IZ HPV   6/02/11         Blue Cross

I've tried using the Minimum formula but it just goes through and repeats Blue Cross 3 times because it starts with the letter b.

Thanks for the advice!  I am definitely in need of doing a summary of only the number of vaccines shown in the groups, but every time i do a count on Service or sum on Price, it does it for all records.  How do i only get it to look at the results in the groups?