With your spreadsheet open,
Click on Format from the menu bar
From the drop down menu, click on Conditional Formatting
From the drop down menu, click on Manage Rules at the bottom of the menu.
The Rules Manager box should appear.
In the Show Formatting Rules for: box, select This Worksheet
All the conditional formatting rules for the currently displayed work sheet should appear.
There will be an Applies To box next to each rule.
Append the two columns A&B to your range in the Applies To box
You should currently have something like: =$C$3:$P$3
You want it to look like: =$C$3:$P$3,$A$3:$B$3
Which is your current range selection
Your appended range selection
DO NOT USE THE ARROW KEYS TO MOVE AROUND IN THE APPLIES TO BOX.
Excel will interpret that as selecting a cell and foul things up.
If you make a mistake, just use the Backspace key.
See how that works.
But even if there was, how would you set hierarchy if all three colors show up in a row?
That is the function of the RULES which you apply to your range of cells.
See here for a good introduction to Conditional Formatting