If your team is made up of several smaller teams and you want to manage communication with both the smaller teams and the whole team, you can set up Google Groups to do this by adding team members to the smaller groups and then adding the smaller groups to the larger group:

This way you can communicate with Team A, for example, separately, or the whole team through Team All. If your team members change, you'll only need to modify the member from the smaller team. If you share in Drive, create events in Calendar, and send email using these teams, you'll always know you're reaching the exact team members you need to! 

To add a smaller group to a larger one, simply add the email address of the group to the add members field in the larger group.  Learn to how to Add Members.

1.  To find a group's email address, go to your groups:  https://groups.google.com/my-groups

2.  Click the gear next to the group name.  If you do not see these icons then you are not a manager of the group

3.  You will see the email listed under Group email