A group is the BlackBerry name for a distribution list. By creating and populating a group, you create a single address that represents any number of people. Groups can only be used as a recipient for an email message though, so don't expect to be able to create a conference call using a group.
Click the New Group menu item while viewing the Address List screen to create a new group. The New Group screen shown in Figure 10.5 is displayed. At the top of the New Group screen is an edit field, where you can give the group a name. This name will appear in the Address list along with all of your other Address Book entries.