Conditional formatting to highlight due dates only considering business days

Hi there,
I have a spreadsheet tracking documents that require review. Documents need to be reviewed within 7 business days of receipt. I would like to use conditional formatting to highlight the comments due date based on number of days from the current date. ie: green 7-6 days, yellow 5-4 days, orange 3-2 days, red 1 day, maroon for overdue.

I can apply the conditional formatting but I can't make it apply only to business days! Any help would be greatly appreciated! I have attached a sample of the spreadsheet format, with dates in the columns discussed above.

Cheers!
Emily

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Excel_conditional_formatting_of_dates.XLSX11.68 KB