In Gmail you can send email as another account.  This article was primarily created to add group email accounts to the "send as" drop down menu.

1. Click the gear and select "See all settings."

2. Click on "Accounts."  Under "Send mail as," click "Add another email address."

3. Add the name of the account/group and the email address:

4. You will see a drop down menu in the "From" section.