Online storage | Question regarding multiple users and sharing permission

Hello all,

I'm needing to set up some form of online storage. Something like Google Drive offers the file organization that I need (easy creation of folders, sorting files, etc...) but I also need to be able to set up multiple users. I realize I can do this with multiple Gmail accounts but that's impractical for our use as files need to be shared with users who may or may not be computer savvy.

This is for a condo strata council.

I need to set up a few permission levels:

Admins: Users who upload, edit, organize and delete content, create folders, etc..
Members: Users who can view all files and edit files they have permission to edit
Users: All other residents who can view files selected by the admins

Basic services like Dropbox, Skydrive, etc.. don't offer multiple user management.

Another option may be to build a site using a CMS such as Drupal or Joomla, but even I (A "comptuter guy") find the administration pages and control panels confusing and I don't think it would be practical for computer illiterate users.

Any tips would be great.

Thanks.