1. Click any single cell inside a data set.
2. On the Data tab, in the Sort & Filter group, click Sort.
The Sort dialog box appears.
3. Sort by Last Name (or any other column), sort on Cell Color (you can also sort on Font Color and Cell Icon), and select the green color for the first level.
4. Click 'Copy Level' two times and select the other colors.
5. Click OK.
Result.
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