HOW TO INCREASE THE LIMIT OF 25 CALLERS WAITING IN MY CALL QUEUES?

Currently, the queues are limited to 25 callers waiting in line for the designated wait time of 15 minutes. I am aware of creating multiple queues to just keep it rolling over 2 queues, but it would be better if we can have more than 25 people waiting just in case it reaches that limit during the busy season?