As long as all editors have access to the same media files, they can collaborate on the same Team Project. A NAS or SAN will work, or they could use a cloud-based storage solution like Creative Cloud Files or Dropbox, and proxies are supported. They could also use cloned hard drives. The Team Project will search all mounted drives automatically to find media it refers to. If the media isn't found automatically, the editors can use the Media Management drive to locate the local path that holds the media.
Team Projects synchronizes all of your edits and metadata to the cloud, but it does not synchronize the media.