A method of nested feedback loop decomposition of a given system is developed based on a special coordinate basis which reveals the finite and infinite zero structure of the system. This decomposition leads to a model order reduction procedure by which any arbitrary subset of the system invariant zeros can be retained in the model while the infinite zero structure of the model and the system are one and the same. Thus this method of model order reduction is a method of reducing the dynamic order via the zero structure of the given system. Several examples illustrate the method