Groups of users

[kmaynard]

I want to have several groups of users (3 or 4), with several push notifications from different sources directed to each group. Users may belong to more than one group. How do I structure this? Do I need a separate account for each group? I can't see how users can be restricted to particular APIs. Security isn't the problem - I just don't want them troubled by receiving irrelevant notifications. TIA.