Like many other Registration Question responses, a sub-group is now automatically created when a user uploads a document in conjunction with their registration. You can create multiple Upload Document questions, and this data will be stored accordingly in the sub-group.
The sub-group will be named “RegDoc-DocName." You may easily identify who is associated with the sub-group (i.e. who has uploaded that particular document) in the same way that you manage your sub-groups--by utilizing your familiar Sub-Group Manager (found on the Blue Toolbar > Gear Icon), the Groups Export or Members Export (Blue Toolbar > Cloud Icon), the Groups Tab of the Member Dialog box.