Howto organize user groups


I am a full newbie to elgg, but wish it wasn't so and am pouring through documentation. I thought perhaps it would help to get some direct help to get the ball rolling quicker.

There are a lot of customizations I wish to do, but those are more technical in nature and the docs are helping to get started.

Perhaps experienced users can suggest how to best organize users/groups so that I can have:

  1. UserGroup1: Normal Users (Joe Plumber) who sign up and have their profile, with standard widgets and features
  2. UserGroup2: Only a preset amount of widgets in preset layout, with slightly different theme than standard
  3. UserGroup3: Not so much users as a Catalog of products, however want each product to have a sort-of profile page.  Will be a profile page for a manufacturer which then has links to a profile page for each product that manufacturer makes.  No one logs in as these 'users' but is only controlled by admin

I hope this makes sense. Thing is, I'm not so sure if ElggGroups does what I'm looking for, so perhaps I'm using the wrong searchterm - I don't want a 'group' where users join and can post/discuss in that group (actually I do want this, but not to solve the above). I more want users who are tagged/indexed into certain classifications and the widgets/themes available differs depending on what index they are in.