Background color of cell based on colors in column

I have a data base in which I classify cells in three colors (green, yellow, and red) on my own. I would like the first cell in each column to indicate if there is a red or yellow cell in it's column. Because red cells are more important then yellow cells, if there is a yellow and a red cell in the column, I would like the red to over ride the yellow and the first cell would indicate red. So basically, if there is a red cell in the column, no matter what other colors there are, the first cell should show red. If there is only yellow or yellow and green cells, the first cell should show yellow. If there are only green cells or green cells and clear, the first cell should show clear. Thanks for your help and if you have any questions, I will try to clarify. Thanks again!