I have created a new database using the template 'Personal Address Book'. I have entered some email addresses in this new database. When I create a new email message, and select the address button to choose the address book that I want, there is a option on 'View by organization'. When I have chosen the address book that I want and check on this option, it shows '(Not Hierarchical)', what does it mean? In this option, how do I show the different groups which have the email addresses under each group?