Date validation in Data Services

I am trying to validate dates through the data services designer and am having no luck.

I have a file that has a date on it for a specific key. I am trying to find the most current dates for that key only meaning that the old record is expired. Any help with this would be helpful.

Thanks

Travis

Example:

Key1 Key2 Key3 Date

01 02 ABCD 2009.02.02

01 02 ABCD 2009.02.03

01 02 ABCD 2011.05.03

The record I want to return is 01 02 ABCD 2011.05.03