depends on how many students you have
One thing that comes to mind is that work can be broken into separate parts quite easily (and somehow automatic) due to the separate activities.
You could say "ok, group A makes an activity that views the inbox, group B shows one mail, group C a calendar, Group D creates the Content Provider for Mails and Group E a service to check for new mails periodically, etc. etc.".
Moreover, if you dont have enough manpower you can concentrate on a few tasks and let the rest be done by the next group (the calendar or the service for example) without them having to understand every single line of what has already be done.