don't know if this helps:
in the past i've often been asked to do this.. the situation usually is that (in my company) the person has a spreadsheet with cells manually coloured Red or Amber or Green
i always advise to use Conditional Formatting (FORMAT/CONDITIONAL FORMATTING) in this instance.. set these cells to go their relevant colour when a person types in an R or A or G.. you can set it to colour the text the same as the background so that the text is "hidden"
Conditional Formats only extend to three choices though.
then you can use SUMPRODUCT or COUNTIF formulae (Countif is the easiest to understand for a noob) to count the text in the cell, or whatever
maybe that helps