Relevant Product: Exclaimer Cloud - Signatures for G Suite
Scenario
You have granted users permission to send email from a groups email address by following the instructions in the following Google article, however the sender's signature is applied to the email.
Resolution
When an email is sent as a group in Gmail, the Return-Path header is populated with the primary SMTP address of the user sending the email as the group.
When emails are processed by Exclaimer Cloud, the user whose signature should be applied to the email is determined by the email address populated in the Return-Path header, so the signature of the user that sent the email will always be applied to emails sent as a group.