To create a group email head to Settings > User Groups and then select 'Add User Group'.
Once you have selected 'Add User Group' you will then be directed to a page where you can add the Description and the Email Address. Add the email address that you require the group email to be sent from and replied to. When you are done, simply hit 'Save'.
Next, head back to Settings > Users and select the pencil icon next to the user you require the group feature for! Once you have done that you will be able to view all the available groups for the selected individual and here you can set any relevant groups to 'Y' to enable them and 'N' to disable them.
A confirmation to add the user to the group will display.
You have now completed the set up of this feature!
Next time you need to send an email, select the email address as per usual and then simply select the sender email address you require from the drop down (this will then appear in the inbox of the recipient).