In MAS, it is important for an agent to track and keep watch on others, and to infer their high-level objectives and intentions. As far as tracking multiple agents is concerned, in order to decide whether to coordinate or to compete, it is desired not only to learn every agent's intention, but also to infer the group's intention. In this paper, the mental states of agent-group, the group rationality are introduced, Which makes it possible to track both individual and group intentions under the constraint of limited resources.Tracking individual intention and tracking group intention are interdependent,Which enhances the accuracy and the efficiency.The tracking of multiple agent's to multiple agents is also discussed.And the work of Tambe et al is improved.