I need to create a criteria for a Countifs statement that will exclude and record that does not match a timestamp. I need the function to only look at the time of day instead of the date and time, and I am having trouble with.

Example)

6/19/13 5:07
6/19/13/5:14
6/19/13/5:25
6/20/13/10:20
6/21/13/22:15

In every report the earliest record will always be "5:07" so I need to have the criteria only look at that part of the time stamp. If anyone could help with this that would be great!