Using Breaks/Context operators in WebI

Hi guys,                        

Had an urgent question that i needed help with.

Right now in WebI i have a table with a column giving end times

for Example:

End Time

5:02 AM

5:44 AM

6:05 AM

6:15 AM

6:45 AM

7:10 AM

7:22 AM

..

..

Instead of detailed times i need to replace this column with a counter for every hour... Basically

Hour               Count

5th Hour           2

6th Hour           3

7th Hour           2

How do i acheive this? Using breaks doesnt work right and the Context operator "In" isnt giving the right results. Do i need a variable?