The control of manufacturing systems consisting of a certain number of parallel machines processing a given number of jobs is addressed in this work. A decentralized scheme is defined in which at a local level, the optimal control of each single machine is considered, whereas, at a higher level, the overall manufacturing system is taken into account. At the local level, an optimization problem with quadratic cost function and nonlinear constraints is stated as a multistage control problem and solved by means of dynamic programming techniques. The objective of the higher decisional level is, instead, the optimal splitting of jobs on parallel machines.