Meaning of two queues served with the same server

My university HPC, which is controlled by pbs-pro, has several queues, and some of them share servers. How does that work ? when the server is free, which queue gets it ?

It will be based on queue priority and/or based on the qlist ( node mapping across multiple queues)

Thank you. Where is that queue priority defined ?

Please run these commands, you should be able to see in the queue configuration:

 qmgr -c "print queue  NAME-OF-THE-QUEUE"
 qmgr -c "print server" # check the queue configuration