Is there a way to control how FSG's are processed?

We have an issue where there is a large number of FSG's created at certain points in the month, and they end up overwhelming the standard manager and causing other requests to have to wait too long for their turn in the queue. We have created a specialized FSG_Manager that runs the FSG, but at some point the XML generation of the FSG goes beyond the specialization and moves to the Output Post Processor and standard manager. What are the best practices for managing FSG's?