Organize your contacts into groups to find them more easily. The groups are available on any device, but you can only manage them from the desktop or web app.
Create a group
Click Chat 
, click the Contacts tab, and at the bottom of the tab, click Create a new contact group. Name your group and click Create. You can always rename or delete your group later.
Add people to a contact group
Click Chat , click Contacts, and then click More options 
beside the group’s name. Click Add a contact to this group, type the name of a team member, and then click Add.
Rename a contact group
Click Chat , click Contacts, and then click More options beside the group’s name. Click Rename this group. Type a new name and click Save.
Note:
You can't change the name of the Favorites group.
Delete a contact group
Click Chat , click Contacts, and then click More options beside the group’s name. Click Delete this group.
Remove someone from a contact group
Click Chat , click Contacts, click More options beside the person’s name, and then click Remove from this group.