Coloring Cells By Conditions?

With a range of cells (a1:ao41) I want to color several cells depending on the value of that particular cell and another color when that particular and a corresponding cell have both the same value. It's some sort of sociogram The first row and column both contains names of students. Let say the students have to choose the three most populair ones to work with and the three most unpopulair ones. Positive ones get the color blue, negative ones get the color yellow. That's easy to do with conditional formatting. But now comes the tricky part. If for instance Student 3 chooses Student 7 and Student 7 chooses Student 3 the color of both cells have to be green if both positive and red if both negative. That's also do-able with conditional formatting, but it most be much easier to do with VBA. I just don't know how .