Maximum Number of Running Jobs a user can submit to a particular queue (512 cores in this example)
qmgr -c "set queue your_queue_name max_run_res.ncpus = [u:PBS_GENERIC=512]"
Minimum Number of Running Jobs a user can submit to a particular queue ( 4 cores in this example)
qmgr -c "set queue your_queue_name resources_min.ncpus=4"