Permissions to use "fields grouped" or "regular" fields

Hi,

Couldn't come up with a more descriptive title, sorry.

What I'm looking for is role permissions that will activate field group module for roles. If u role doesn't have the permission than the fields are shown as if field group module never existed.

Use case; user profile
In a site I'm working on new users can register by just entering their first, last name, email address and password. The fields the anonymous user may fill in are devided into 3 field groups. Now when the anonymous user becomes an authenticated he or she may enter fill more fields that have become available for the authenticated user role. Website maintainers may use even more fields that are not available for authenticated users.

Big deal you'd say, but when using vertical tabs for instance, a user has to go through 3 tabs to complete the form, each tab containing maybe one or two fields. That's a bit overkill.

Is there an way to remove the field groups for certain roles but leaving the fields within in tact? Or is my permissions suggestion feasable?

Cheers