This paper deals with obtaining the optimal control configuration for process networks comprising lumped and distributed parameter systems. Equation graphs that capture structural interactions among the input and output variables of first-order hyperbolic PDE systems with different types of actuations are proposed, which are combined with equation graphs of lumped parameter systems. Using these equation graphs, parameters that quantify structural coupling (relative degrees, characteristic indices) are calculated, on the basis of which, the optimal decentralized control configuration is identified. Agglomerative hierarchical clustering is then applied to obtain candidates for block-decentralized control configurations. A modularity maximization algorithm is used to select the optimal block-decentralized control configuration.