digital signage

Hello, I manage a digital signage network. I want to develop an internal solution to manage the broadcast on my entire Raspberry pi3 B+. We must develop the system part on the Rb B + and also the software part in saas mode to control all players. The broadcast must be able to be done individually or by grouping players. Several features are expected such as the creation and programming of videos from a stream. The company owns are propore server. The entire system will be deployed on it. Our society must be able to control and program a playlist for each player, but also for groups of players. Each trader also has access to an interface to program the spaces reserved for him. The system must be stable to support more than 500 players. Each player uploads information such as the actualista of the calendar, last sync of videos, screen status. The videos are stored on the Raspberry pi3 B+ Each Raspberry B + must be equipped with a battery in order to play the programmed videos even when the internet connection is lost. deadlines for implementation : ASAP