This paper focuses on simulating agents transporting passive objects in a virtual environment with pedestrians. The agents adopt the pushing manipulation patterns to transport the passive objects. We propose techniques to achieve two kinds of cooperation. First, the agents transport the passive objects to the goal positions. During the transportation process, the agents may adjust their formation to transport the passive objects effectively. Second, the agents avoid collision with each other and passive objects in an unfreezing manner. Experiment results show that our technique avoids the freezing problem while the agents are transporting multiple objects.