CCTV or conference call systems, what to use?

Dear habrovchane, maybe you can help me solve my problem.

Given

Several objects. In them from 10 to 20 rooms.

Task

1. It is necessary to install a surveillance camera in each room (preferably a duplex with audio).
2. To organize the flow of video / audio in normal quality from each camera to the Internet.
3. By login and password to give users the opportunity to receive audio / video from one of the cameras. (More than 100 users can be connected to one camera)

')
Need to find a system solution.

I tried to go on the part of video surveillance systems (security), but experts said that after the N-th (or rather 10-15) connected user to one of the object's servers (for watching video), the server would fall. A pier is not for such purposes it.

In the case of the approach of standard video surveillance systems, the structure is as follows:

1. Cameras (10-20pcs) are connected to the server, which is located on the site.
2. The server is connected to the Internet
3. Remote users connect via the Internet to the server (to which the cameras are connected) and access the video from the cameras.

Advise plz.