Meeting Requests/Different People/Different Days

I am trying to figure out how to make a meeting request that tracks an entire
process(12 days) that has 3 different group inputs/timelines. First group is
5 days, 2nd group is 5 days, and 3rd group is 2 days. All groups would be
requested for the entire timeline, but their due dates and tasks would only
be associated with thier particulare group timeframe. All of this to keep
each other in the loop of where things are in the process, all while not
creating multiple entries in the calendar feature. Thanks!!