You can manage what groups/lists a customer belongs to directly from their customer record. This method only allows you to add/edit/delete one customer at a time from a group/list. To do so:
1. Select Customer ► Find, look up a specific customer, and double click to open his or her record.
2. Select the Other Keys tab.
3. The pane on the right side contains all currently active groups/lists. You can assign this specific customer to a group by checking it, or uncheck it to remove them. Also, you can create new groups/lists here with the New Group/List button at the bottom.