Group records with custom yearly grouping

Hi Experts,

I am creating a report where I need to group records yearly but it needs to depend on a specific date.
More in detail, my report is pulling employee records for their hours paid.
I need to show a total of hours paid yearly on the date he/she was hired

So if an employee was hired on 7/1/2010 then it needs to group and total as follows:

Range                                    Total hours paid
======                                  ===============
7/1/2010 - 6/30/2011                    456
7/1/2011 - 6/30/2012                    789
7/1/2012 - 6/30/2013                  1012

If you could guide me to the proper grouping formula I need to create I would really appreciate it

Thank you

CRM