What's the name of this kind of system?

i'm about to start a project for sharing files, announcements, and other stuff between branches of a company, it must be a web based system, with all the layers as profile management, employee communication, etc... What i don't know is what's the name of this kind of systems? It's a web based system wich will only allow access to the company's personnel(still don't know how to do that - help please), and must connect the different branches.