A method and system is provided that may be used to dynamically modify membership of a collaboration group participating in a collaboration session using dynamic situational information associated with collaboration session and/or collaboration group member candidates. The dynamic situational information may include collaboration session information, environmental information and context information. A change in collaboration session purpose may trigger a modification of group membership in accordance with a concomitant change in group membership criteria. A change of situational information associated with any group member candidate may trigger the modification of group membership, to add or delete the candidate from the group. The method and apparatus of the present invention may advantageously be embodied in a service that is used by existing communication and collaboration systems to enhance workflow efficiency by exploiting system knowledge to improve the use of resources, reduce the incidence of errors and eliminate redundancy.