For example if the 1_tickets queued reached 50, it will trigger an alert.
Thank you.
Figuring you are talking about the number of messages waiting to be processed in hub's queue this might help:
Is there a way to change queue failure from severi - CA Knowledge
If your goal is to monitor the queues, with a possibility to send an email of a threshold is reached, you can check: QueueCheck LUA script v2.2