Sorry if I should be posting my question in a different forum, please just let me know...

I am trying to highlight on an Excel spreadsheet numerical values from experimental results (normally in decimal form with two or at most three decimal figures) that are equal or close in value within a certain tolerance (that I would like to be able to specify).
The built-in macros of excel allow me for detecting the exact "duplicates" (to the last digit) but I cannot detect those numbers that are close. For example I cannot make it recognize that 34.561 is almost the same as 34.558 and I would like to see them highlighted with the same background color. I don't want to round the values either, but keep the original numerical information that has been recorded in the experiment.

Is there any macro combination I could use?
Thank you for any help/guidance!