Revit Server. Let's review quickly what it was meant to do and the problems that it solves. Then we'll take it to the next level.
Revit Server was designed to help a SINGLE company with distributed, satellite offices work on a single model. In that scenario, everyone is on the same wide area network with no worries about security or other IT issues to get the server up and running. In the traditional model to the left, we are using some sort of VPN for synchronization, or an FTP site to share a model that has been sliced into pieces so that each office can work on their piece of the project. This can work, but only if the pieces of the puzzle are cleanly delineated, which is very rare on a project of the size and magnitude that would require
multiple offices' involvement. The offices are also having to re-link updated models or having to wait for a s-l-o-w synchronization via VPN to a central file housed at Office A.
Those are just the basics. There is more to discuss but that can wait for later, or you can give us a call.