There was a feature request back in 2019 by Ann Richardson (https://tithely.canny.io/chms-feature-requests/p/reports-scheduled-emails) which got closed because it conflated more than one feature request. I can't see if she ever reopened segmented requests, and can't find an active feature request for this one.

Here's what Ann said:

I would like to request, with regard to Reports - Scheduled emails, tailor the scheduled email report title (eg; we send 'Group Individual Attendance' reports to about 60 group leaders regularly. Looking at the list of scheduled report emails where the whole list has the same title is... not very helpful.

That pretty much says it. If, from the Admin Area, you go to the Reports menu on the left sidebar, and choose Scheduled Emails, you see (in my case) 5 instances of "Group Individual Attendance", with different recipients shown. It doesn't show which group. So if you want to add a recipient to one particular group attendance email, you have to click each in turn until you find the one you want to change.