The four types of group in Microsoft 365
When you create a group in the Microsoft 365 admin center, you see four types. Three of them matter for email. There is also the shared mailbox, which is technically not a group but is often used for the same purpose.
- Distribution list. An address that forwards every message to all members. Everyone gets their own copy. There is no shared archive: anyone who joins later does not see earlier messages.
- Microsoft 365 group. A group with its own shared inbox, a shared calendar, a SharePoint site for files and a plan in Planner. Members can also receive group messages in their own inbox. New members see the full history.
- Mail-enabled security group. Works like a distribution list, but you can also use it to grant access to, for example, a SharePoint site or a shared folder. Useful when the same people need to receive email and access certain files.
- Security group. For permissions only, without an email address.
Which one do you choose when?
- Informing everyone: all@, a location address or a list for management. Choose a distribution list. If you want the list to update itself, for example based on the department or office in the user profile, use a dynamic distribution list in the Exchange admin center.
- Working together as a team: a project team or department that shares email, a calendar and files. Choose a Microsoft 365 group. If the team already uses Microsoft Teams, every team already has such a group in the background; do not create a second group for the same purpose.
- Replying on behalf of the company: info@, support@ or invoices@. Choose a shared mailbox. The team then replies from the shared address, everyone can see what has already been handled and no extra licence is needed.
Settings to check for each group
- External senders. Decide per group whether people outside your organisation may email it. For a new group this is often turned off, so customers get an error message. Only turn it on for addresses that must be reachable from outside. Keep an internal list such as all@ closed, so nobody outside can email the whole company in one go.
- Two owners. Give every group at least two owners. If the only owner leaves, nobody manages the group any more. So include groups in your joiner and leaver checklist.
- Visibility. A Microsoft 365 group is private or public. In a public group, any member of staff can add themselves and read the files. Choose private for anything with sensitive information.
- Guests. If you add external parties to a Microsoft 365 group, they get access to that group’s files. Make deliberate agreements about this, as described in guest accounts in Microsoft 365.
Converting existing distribution lists
If a team actually uses a distribution list as a shared inbox, you can in many cases upgrade it to a Microsoft 365 group in the Exchange admin center. The email address stays the same. This does not work for every list: a list that has another group as a member, or that is synchronised from your own Active Directory server, has to be adjusted first. Use the opportunity to clean up lists nobody uses any more; an overview of members and owners quickly shows which groups are still needed.
How Floor ICT handles this
Floor ICT takes stock of all groups, distribution lists and shared mailboxes in your environment. Together we choose the right type for each address, convert distribution lists where it makes sense, set external senders and visibility correctly and make sure every group has two active owners. When someone leaves, we check their groups as well. That way email arrives in the right place and your environment stays organised.