Abstract: A messaging system with messaging accounts for users of the messaging system comprises a group messaging service for transmitting and receiving messages via a network between users in each of plurality of messaging groups, those users having messaging accounts associated with that messaging group. An organization management system with member accounts for members of an organization comprises a registration service for registering user identifiers with the member accounts. An information retrieval service of the organization management system generates a group information request comprising a user identifier registered with one of the member accounts. A system interface communicates to the organization management system, in response, information about at least one of the messaging groups associated with a corresponding one of the messaging accounts comprising a matching user identifier.