multiple cells controlling one cell

You would use conditional formatting to control the color (translation: colour ) of the cell. You would select "Use a formula to determine which cells to format." Please see Excel help on "Conditional formatting" if you are not familiar with this.

However, conditional formatting cannot refer to cell addresses on other worksheets. You have two workarounds for this. First, you can assign named ranges to the values and the tolerances, or you can calculate a TRUE/FALSE determination of whether things are out of tolerance and assign a named range to that. Then you refer to the name, instead of a cell address. The other option is to do this determination on the same worksheet that contains the cell you wish to color, and refer to that in the formula.

If you provide more detail and a sample workbook I can give a more specific answer.