Best 3 Of The Last 10 Years

I am working on a retirement calculation sheet. For retirement calculations the employees need to figure out their highest yearly income for three out of their last ten years. The three years can be based on any consecutive twelve months but each of the three years must be the same months, (example, Jan thru Dec, or July thru June). The three years cannot overlap.
Here is what I have so far. Column A, paydate. Column B, amount. Column C, year to date amount. Column D, amount for past 12 months.
I would like to list the three highest years in the first 3 rows of Column E.
Any help is greatly appreciated.

Pay Date Gross Year to Date Gross
Past 12 Months Highest 3 Years 08/10/06 3,594.58 3,594.58 3,594.58
08/24/06 3,332.79 6,927.37 6,927.37
09/07/06 2,595.59 9,522.96 9,522.96
09/21/06 2,457.36 11,980.32 11,980.32
10/05/06 2,457.36 14,437.68 14,437.68
10/19/06 2,457.36 16,895.04 16,895.04
11/02/06 6,212.51 23,107.55 23,107.55
11/16/06 3,206.09 26,313.64 26,313.64
11/30/06 4,104.56 30,418.20 30,418.20........