All the events which are marked ``grouped'' and whose date is ``today'' when REMINDERCHECK is run, are put into a single requester24 (or to as few requesters as possible).
Acknowledging this requester means that you acknowledge all the events in that requester. There is no way to acknowledge (or not to acknowledge) single events in group requester.
NOTE: The ARexx event associated with group requester is any of the ARexx events of the events in the requester. There is no way to specify which one. Only one ARexx event is generated for each group requester.