Is there any way or existing function to get the list of user under any supervis

Is there any way or existing function to get the list of user under any supervisor. I need it to prepare the report.

There are other complicated way to accomplish it but I need to know if there is any direct way.
Also can anyone help to get the user name from any Group in Rule expression.
Thanks.

OriginalPostID-163828

OriginalPostID-163828

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