We are not yet in the Archicad fold. Still researching, so excuse my ignorance.
Recently we bought an expensive NAS with fast I/O performance that acts as a file repository/server for the office.
We work in 2d at the moment and have a peer to peer Windows network.
I bought the NAS because Microsoft artificially limits the number of machines in a peer to peer to 20, and we are just over that. The NAS doesn't care.
We don't need to access each-other's windows machines.
I don't want to go to Windows Server, with all the administrative overhead.
We don't need individual user profiles - all the machines use the same logon and password. Works fine for us.
On any project there may be as few as 1 person to very rarely up to 4 people working on the same project at the same time.
If we move to Archicad - where we want up to around 4 people working in the same model, is it possible to maintain our NAS/Windows peer to peer environment?
I'm not exactly sure what you mean by "peer to peer environment", but in terms of ArchiCAD and storing references - it doesn't really matter where or how they are stored, as long as the paths on each ArchiCAD client are the same.