The Kuramoto model is one of the most widely studied model for describing synchronization behaviors in a network of coupled oscillators, and it has found a wide range of applications. Finding all possible frequency synchronization configurations in a general non-uniform heterogeneous sparse network is an important yet difficult problem due to the complicated nonlinear interactions. In this paper, we develop a general framework for decomposing a Kuramoto network into smaller directed acyclic subnetworks that will form the foundation of a divide-and-conquer approach for studying the frequency synchronization configurations of large Kuramoto networks.