Each Tower, Router, Access Point, etc should have the ability for a company to track the maintenance (be it an emergency or planned.)
Furthermore - the ability to make notifications to ALL customers downstream of said device would assist every ISP utilizing Splynx in being seen as a Proactive vs. Reactive company.
This feature you are asking is long time there. When you create service for customer, there is dropdown menu to select router and sector, where customer is connectet.
Support/Message in those many fields above text field you will find field called router. just tick selected router, and email will be sent to all customers, who have service attached to particular router.