Google Groups setup for administrators - Manual (Page 5)

Outside this domain Private - No one outside this domain can access groups.
Creating groups Only domain admins can create groups
Member & email access
Group owners can allow incoming email from outside this domain
Next, you set who can create and join groups.
On the Settings for Groups for Business page:
1. Click Sharing settings.
2. Choose the following settings. You can
always change them later.
About these settings:
●
You can designate group managers on your
team who can add/delete users for each
group.
●
Only admins can add external users to a
group. You can change this setting later.
Choose recommended settings
5. Train your team 1. Turn on Groups 4. Collaborative inboxes 2. Set up auto-reply 3. Add external users