The current job priority attribute sets the priority of the process on the operating system.
A different kind of priority (scheduling_precedence) is needed for jobs requesting the same process class or the same lock.
<job name="test" scheduling_precedence="5"/>
Default is 0
The job with the highest precedence will be the first to aquire the lock/process_class
This should also be available in the start job command:
<start_job name="test" scheduling_precedence="10"/>
(This will overwrite the precedence of the job for the enqueued task)