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Chatting with Distribution Lists and Other Groups
Message center MC408435 (4 August) covers a new way to start a Teams group chat. As you might recall, a group chat is one that has more than three participants. In this case, you’ll be able to start a new group chat by choosing an Exchange Online distribution list, a mail-enabled security group, or a Microsoft 365 group (Figure 1). Dynamic distribution lists cannot be used.
Roll-out is scheduled to start in late September 2022 (revised date from August 29) and to complete by late October. Microsoft hasn’t yet updated the general availability date of September 2022 published in Microsoft 365 roadmap item 62354.
After banging the drum to move people from email to Teams since 2016, it’s ironic that the Microsoft’s announcement notes that “organizations rely on distribution lists,” saying that DLs are “a tool to create groups of users that mirror organizational knowledge and workflows.” It’s almost like they were discussing Teams! Microsoft attempts to return to safer ground by noting that “leveraging DLs can increase workflow efficiency and bridge the gap between legacy knowledge of organization structure and a new Teams structure.” It’s a model example of how to confuse people, but it’s nice that Microsoft acknowledges the usefulness of distribution lists.
Starting a Group Chat
When you start the chat by entering the name of the group to use, Teams expands the selected group to find the members chat supports. This set includes tenant member accounts and guest accounts. Figure 2 shows what happened when I started a chat with the Microsoft 365 group that we use to manage the development of the Office 365 for IT Pros eBook. Teams added all the other authors and the technical editor to the chat, which made it very easy to get a conversation going.
The only downside is that we already have a fully-built-out team complete with many channels to host conversations. Perhaps creating a group chat from a team-enabled Microsoft 365 group is too much of a good thing.
Expanding Distribution Lists and Removing Unsupported Members
When it expands a distribution list, Teams includes the members of any nested distribution lists and drops the unsupported member types that can be in distribution lists such as public folders and mail contacts. Obviously, public folders are a poor choice as a chat participant. Mail contacts are excluded because although Teams supports federated chat with external users (which are what mail contacts represent), federated participants can’t be part of group chats.
Reflecting the current limit for group chat participation, Teams can import up to 250 people from a group (well, 249 plus the person starting the chat).
Tags Work Too
A tag can be system-defined or specific to a team. It’s a method to address a subset of team members. For instance, every month I remind chapter owners (identified by the writers tag) that’s it’s time to update chapters for the monthly release of the Office 365 for IT Pros eBook. You can also start a group chat using tags, a capability that I’m not sure many people use (maybe because tagging isn’t used heavily?).
Figure 3 shows how tags show up when you type the name of a person or group to start a chat. At the top of the list, you see the group chat I started from our Microsoft 365 group. Following that are a set of tags from different teams that I am a member of. Selecting the tag creates a new group chat with the tagged people as the participants. You can’t use the special Team Owners tag to start a group chat because it’s only available when you work with conversations inside a team.
If you need to update the participant list of an existing group chat, you can do this with a tag. However, you can’t add participants from a distribution list, Microsoft 365 group, or mail-enabled security group after the initial creation of a group chat.
If you’re unsure of how heavily people use tags in the organization, you can grab the useful script discussed in this article.
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Do chats that were initiated using a distribution group automatically update the list of members in the chat when the distribution group gets updated?
No. Population of chat participants is a one-time operation.
Does this take into account the existing security of the DL? Can users that can’t send to a DL still send to it from Teams? Or can they still expand the DL list and send to it in Teams if they don’t have permission to send to the DL?
Do you mean a control like AcceptMessagesOnlyFrom? If so, these have no effect because the controls are implemented in the Exchange transport service and Teams doesn’t use that to resolve the members of a DL.
Yes, basically. We lock down most of our DLs, so we don’t want users to be able to bypass our security and use them in Teams to start a huge group chat. Is there a way to prevent this? Do we need to hide the DL membership? Or somehow limit Teams from expanding our DLs for users that don’t have permission to send to them?
Hiding the group membership doesn’t work. I suspect that Teams uses a Graph API to read the membership and insert the members into the chat header. Right now, there’s not much you can do to stop Teams users starting chats with DLs that use Exchange-level controls to control access. Teams just ignores all the controls.
Thanks so much for testing this. I appreciate it.