Simulation is a useful tool for engineering systems, and it is used in numerous and diverse fields. Simulation of large systems can result in better designs, and make the design process more efficient. One important use of simulation lies in comparing different simulation models that represent competing or alternative designs before the actual deployment and implementation. Simultaneous Simulation of Alternative System Configurations (SSASC) provides a methodology that exploits the structural similarity among the alternative configurations and results in an efficient simulation algorithm that evaluates alternative configurations of a system simultaneously. In this paper, we designed and implemented an efficient data structure for simulation state management to speed up SSASC. This approach is orthogonal to parallel or distributed simulation. The resulting improved algorithm could form the basis of an efficient parallel simulation framework.