Chatter broadcast group is a type of group that should be created to meet this request. Chatter broadcast group is a group where only group owners and managers can create posts, but anyone can comment on posts. This can be useful for sharing important updates or announcements with a large audience without cluttering the feed with other posts. Reference: https://help.salesforce.com/s/articleView?id=sf.collab_groups_create.htm&type=5