Google Groups setup for administrators - Manual (Page 13)

Update the Sharing settings for Groups
First, you’ll allow people in your organization to add
external users to a mailing group. You will designate
the group owners later.
1. Sign in to your Admin console with your
full email address and password.
2. Click Google Apps on the console’s
dashboard.
3. Click Groups for Business in the list
of services.
4. In the Groups for Business settings,
choose Sharing settings.
5. Leave the settings as before, but
now make sure these two options are on:
Group owners can allow members
from outside the domain.
Group owners can allow incoming
mail from outside the domain.
Important: You need to train your group owners
on managing their mailing lists in Groups for
Business. We share some training resources at the
end of this guide.
5. Train your team 1. Turn on Groups 4. Collaborative inboxes 2. Set up auto-reply 3. Add external users