Salut, Bernard

I believe the dataminer.services expansion recommended by Jarno might be the best option if Teams is in use - at some point, perhaps a fork will be needed for companies who prefer Slack over Teams.

In case of a plain and simple DMA, you only have the list of "All Connected" users - from there I don't think there's an option to simultaneously "broadcast-message" all of them in one go - but the list of users could be re-used for a slack or Teams Integration (unless a "message all connected users" is already in the roadmaps for this "embedded" chat that runs within the DMS)

The current option is only to start a session with a single user, not with all of them: (disconnect is helpful when refreshing user settings)

HTH