Managing Oracle job queues

In Oracle there is a facility which allows the DBA to set the job intervals and job processes. These tell how many jobs can run on the instance, and how often to check for waiting jobs.

Is there a way to get more granular in this management. Can you tell Oracle that you will allow 5 processes to run, but user A can only have one job running, User B can have 2 jobs running and user C can not run jobs. In other words, I am looking for not only instance specific process settings, but schema level process settings. What I really want is for each schema to be allowed to run only one job out of the queue at a time. But several schemas can each have a job running simultaneously.