FDA - Which event rule to code logic?

Hi,

I have created a find/browse form that displays employee competency records.  Each employee can have multiple competency records for the same competency but with different expiry dates.  I would like this application to only display the most recent record in the grid.  Is the way to do this to code the logic in an event rule?  If yes, which event rule should I be coding the logic in?

Thanks in advance!