The multi-point dynamic aggregation (MPDA) problem of the multi-robot system is of great significance for its realworld applications like bush fire elimination. The problem is to design the optimal plan for a set of heterogeneous robots to complete some geographically distributed tasks collaboratively. In this paper, we consider the dynamic version of the problem where new tasks keep appearing after the robots are dispatched from the depot. The dynamic MPDA problem is a complicated optimization problem due to several characteristics, such as the collaboration of robots, the accumulative task demand, the relationships among robots and tasks, and the unpredictable task arrivals. In this paper, a new model of the problem considering these characteristics is proposed. To solve the problem, we develop a new genetic programming hyper-heuristic (GPHH) method to evolve reactive coordination strategies (RCS) which can guide the robots to make decisions in real-time. The proposed GPHH method contains a newly designed effective RCS heuristic template to generate the execution plan for the robots according to a GP tree. A new terminal set of features related to both robots and tasks, and a cluster filter which assigns the robots to urgent tasks are designed. The experimental results show that the proposed GPHH significantly outperformed the state-of-the-art methods. Through further analysis, useful insights such as how to distribute and coordinate robots to execute different types of tasks are discovered.