remove background shading

Is there a way in Excel where columns are shaded a color, but when I put an S or P in a cell that it removes that background color in that cell and the cell to the right, example B9 is shaded blue and blank, c9 has a number and is also shaded blue, but  when I type either an S or P in cell B9  it removes the color in that cell and also cell C9 .  and goes back to  white?