Controlling the NextHitValue in a large simulink file

Is there a way to control the simulation step in simulink? I am having a large file, where each block is user defined Matlab Level2 S-function. Within each block, I have implemented a necessary condition for stability, which enables me to get the maximum time step for which the current block will be stable. This means, that for the complet file, I have to take the smallest time step from all blocks and set iteratively, the NextHitValue of the individual blocks to this value. How can I do that without using global variable?