Call duration warning notifications

Many of our lower tier techs spend more time in calls and working on tickets than we would like, most of the time simply because they're stuck in a call and lose track of time. Having the option to enable alerts/notifications on specific users, groups, and/or call queues that would trigger and notify our techs in some way when the length of their calls reaches a set time limit (15 minutes would be ideal at their level) could very well help them stay on task and move along faster.