I have an application using activity that runs on Linux. I now need to integrate a fax server that must be run on Windows. I want to have a custom job server that runs on Windows while the other job servers run on Linux. I want the Windows job server to filter out non windows jobs and vice-versa for the Linux one. I can do this by subclassing AcquireJobsCommand and implementing the logic myself, but I think there may be some benefit to including some type of filtering mechanism in the job executor system to make this easier and more powerful. In a perfect would there would be a column on the jobs table that could be used to do database level filters along with a hook to do filters via an interface.