How to organize the collection of video from IP cameras and broadcast on 50 monitors (selectively)?

Question

Video broadcast

you do not need to implement the following task: connect 100 ip-cameras (FullHD), save data from them. and broadcast on 50 LCD panels (and not the same), and managing both on each LCD panel and centrally. in addition, third-party video can also be played on these LCD panels.
What are the modern solutions for this:
1) What is the best way to collect video from cameras - a full-fledged server or a DVR?
2) How to organize the broadcast of the collected video in real time on the LCD panel (preferably without a PC for each)?
3) "continuation to the previous question": How can I display third-party content (movies, videoconferences, etc.) on the LCD panel in addition to video from cameras?
4) How to organize control (switching between video streams) both from one place (server) and from each LCD panel (moreover, certain LCD panels should not have access to all video streams, but only selectively)
5) Than should it be managed?
Guys, I really need your help.

Answer 1

Distribution to monitors can be done through matrix switchers (Israeli company Kramer).