By that I mean that you would run the wizard twice, once for admin and once for general users.
The portion not for admin wouldn't expose the access group field, since you wouldn't want people to be able to choose their access group as they register.
The column names are uniquely named to prevent confusion when referring to them later. They could be the same, really the database design can be whatever you want, but making sure each column is uniquely named we just avoid having to talk about ambiguous column names in joined queries.