We propose a new pure Lagrangian method for the parallel load balanced simulation of particle-fluid systems with moving boundaries or free surfaces. Our method is completely meshless and models solid objects as well as the fluid as particles. By an Orthogonal Recursive Bisection we obtain a domain decomposition that is well suited for a controller based load balancing. This controller approach is designed for being used on clusters of workstations as it can cope with load imbalances not only as emerging from the simulation dynamics but also from competitive processes of other users. In this paper we present the most important concepts such as neighbourhood search, particle interactions, domain decomposition and controller based load balancing.