We’ve always offered a Custom Domain feature on Gaggle Mail which worked by redirecting messages from an address you controlled to your @gaggle.email address.
This solution has worked well for us over the years, partly down to its simplicity but it did have a few drawbacks. Upmost of which was that even though you could send messages to your group using your own address, messages sent from the group still used the @gaggle.email address as it’s from address.
You can read more about this feature here. It’s quite simple to set up, just requiring you to create a few DNS records for your domain and validating them with us.
If you have any feedback or questions about this feature or anything else on Gaggle Mail please don’t hesitate to let us know.