Persistent Audible Alerts

Persistent audible alerts should be an option on all devices but specifically on Android in my application (since I know it already works there). I use 9Folders Nine email app and they have an option for persistent notifications that is a game changer for employees who rely on a notification for response to contracts and work orders.

Persistent audible alerts should sound off an alarm (notification sound) repeatedly until the notification is dismissed to immediately get the attention of the person.  For example, a 4 hour contract that requires immediate attention for service should be able to sound off a notification to wake up the individual (much like an actual alarm clock) and continue to do so until it is dismissed manually.  Currently I use my email application (9Folders Nine email) to do this but having it available in Pushover would mean that I could use a different email application (Outlook for example) without fear of breaking my notifications.