(Claire Carouge, ACCESS-NRI Land Modelling Team Lead)
Yes, I like the idea of an option that allows messaging the whole group. Using a post as a mailing list can work but people need to discover the post first before being able to watch it so there could be a delay before they get the information.
Do you know whether people get an email about the message? The user preferences have an option for “Email me when I am sent a personal message” or for email on mentions and watch topics etc. So it does not seem to cover a message sent to a group.