This document explains how to modify a group in Apple iCal (Mac OS 10.5-7) or Calendar (Mac OS 10.8-9).
1. Open the Address Book or Contacts application. You can do this by selecting Window from the menu bar, then Address Book or Contacts. Alternatively, click on the Applications folder from the dock and click on Contacts.
2. Select the group in the left-side list of address books, groups, and directories.
3. Select any entry on the right and press the Backspace or Delete keys. A window will drop down asking to confirm whether to Delete from Group or Delete from address book. Choose the appropriate option.
4.To modify a group name, slow click on it on the left side of the Address Book or Contacts window. When Edit Mode enables, modify the name.
Note: The Edit Distribution List option you see if you CTRL-click or Right-click is NOT related to the group membership or the group name. It is related to attributes for the individual address entries in the group.