Format Cell Color if Difference Found

I have a macro that takes data from two different sheets (current year, previous year) and calculates (subtracts) the difference in values. These are grouped by the values in column A. If the values do not equal 0, meaning no difference between the two datasets, i want the cells highlighted red. In the example I've attached, I've highlighted the rows to display the way the data is grouped for comparison. I do not wish for these to be highlighted from the macro, only the cells in the rows that display the difference in value (not 0) is shown. This cell formatting should occur in every third row as this is the row where the calculations occur. Also, I need to clarify that my beginning cell is B8 which is column headings and B9 contains first value NOT A1 & A2 provided in the image example.


Compare Values and Format Cell Color Where Difference Found.JPG

Select B4 and set ConditionalFormattting with the equation =AND($A3="", B3<>B2)

Copy that CF to the other cells you want to have this feature.

TY for the reply.... This is not suitable as there are 1000 rows in the actual spreadsheet .... and can vary from month to month. I need a macro that will accomplish this formatting.