Different colors for different sets duplicate cells

Okay...I think I can do this in Excel 2007 with color ranges for conditional
formatting but I'm using Excel 2003 and need help coloring some cells. What
I have, very simply, is a single row of numbers in which duplicates can
arise. I not only want to change the color of the duplicates (which I have
already done with =COUNTIF($A$2:$A$11,A2)>1 used as conditional formatting)
but each different duplicate occurrence I would like to be in a different
color. For example, for the table shown:

170
122
96
72
14
78
69
78
128
122

The numbers 78 and 122 are duplicated in the list. My current formatting
highlights all four of the numbers with a particular color. What I'd like to
have the formatting do is to highlight the occurrences of 78 in a different
color than those of 122.

Is this possible in Excel 2003? Can anyone help?

Thanks, Robert.