We present an efficient algorithm for job submissions in Peer-to-Peer (desktop) grids based on limited multicasts. Our approach combines the advantages of two overlay architectures: Chord-like structured networks and unstructured networks with epidemic communication. To predict the multicast properties and to optimize its distribution schedule, we present a probabilistic model of the process of information propagation within the overlay. We show the efficiency and the fault-tolerance of our proposed method and demonstrate the high accuracy of the predictive model.