Creating Mail Groups

A mail group (also called a distribution list or team inbox) is an email address that, when it receives a message, delivers a copy to every member of the group. Groups are managed in Admin → Groups and are implemented via Postfix's virtual_alias_maps.

Groups vs Aliases#

It is worth being clear on the distinction before creating anything:

Use an alias when you want a second name for a single account. Use a group when multiple people need to receive the same messages.

Creating a Group#

1. Navigate to Admin → Groups.
2. Click Create Group.
3. Fill in the form:

4. Click Save Group.

The group is immediately active. Mail sent to support@example.com will be delivered to all members listed.

Adding Members#

Members can be:

• Local accounts — any account in mail_accounts on this server. Start typing the email address in the member search field.
• External addresses — any valid email address on another server (e.g., a team member's personal address or a third-party service). Type the full address and press Enter to add it.

There is no limit on the number of members, but very large groups (hundreds of recipients) can put significant load on your SMTP server. For high-volume distribution lists, consider a dedicated mailing list manager.

Editing a Group#

1. In Admin → Groups, click the group address.
2. Add or remove members using the member list.
3. Update the display name if needed.
4. Click Save.

Changes take effect immediately. Postfix reads the alias maps dynamically (or after a postfix reload if you are using a file-based backend rather than MySQL).

Deleting a Group#

Click Delete on the group detail page and confirm with your admin password. Deleting a group removes the group record and all its member associations. It does not affect the member accounts themselves.

How Groups Are Delivered#

When a message arrives for support@example.com:

1. Postfix queries virtual_alias_maps (backed by the Opterius Mail MySQL tables).
2. The group address expands to all member addresses.
3. Postfix creates a separate delivery for each member.
4. Each member receives an independent copy in their own mailbox.

This means:

• Each member sees the message in their own inbox.
• Members cannot see who else is in the group (unless they check the group membership in their address book).
• A reply to the group message goes to the original sender, not to the group (unless the sender sets a Reply-To: group address).
• No shared mailbox is created. Each person's copy is independent.

Group Addresses in Autocomplete#

When a webmail user starts typing in the To field while composing, group addresses appear in the autocomplete suggestions (marked with a group icon). This lets users send to a whole team without knowing individual addresses.

Use Cases#

Interaction with Autoresponders#

If a group member has an active autoresponder, the autoresponder fires for messages delivered to that individual as part of a group expansion — the same as if the message were sent to them directly. The autoresponder reply goes to the original sender, not to the group.

To prevent excessive autoresponder replies on high-volume groups, coordinate with users before they activate vacation replies, or configure their autoresponder to exclude specific senders or addresses.