Using Custom Groups
To bring up a list of pupils in a custom group in order to update their details, send an email etc:
Open Pupil Manager / Current Pupils or Admissions / Applicants
Go to the search tab heading Custom Groups (not Custom Group Manager)
Tick the checkbox next to the group and Execute Search
NB, if your group includes a mixture of current pupils and applicants, or former pupils, you will also need to tick the checkboxes next to these search options (via the Custom Search tab if you are working in the Admissions module).