renumbering ranking field
I have a database that has a field with a dropdown list that has a list from 1-25. As the users' add new records, they prioritize the record using the dropdown list. They highest priority is 1, the lowest 25. If there are 2 records with the same priority ranking, for instance 4, the newest one is now ranked 4, the old 4 becomes 5, and the rest of the numbers become become the next number higher. How do I accomplish this? Is it a calculated replace after a sort, or a script that's run? We're using FMPro 9, not 10, so action scripts are not an option.
Thanks in advance for any help.