RSMembership component will allow grouping and recurring payment for mosets tree categories or the entire component. It is configurable with custom fields and intuitive php coding that will allow micro billing for specific fields EG: A user could create a free listing but allowed only title and x word count for details. To add website, images etc, they would need to pay for each field. See it in use at
http://pro876.com/artists/
For member grouping without billing, the Mosets permission system will facilitate that within each category's configuration options.