Yes. Of course SXEmacs can use any network file system (such as NFS) you have available, and includes some optimisations and safety features appropriate to those environments.
It is also possible to transparently edit files via FTP, ssh, or rsh. That is, SXEmacs makes a local copy using the transport in the background, and automatically refreshes the remote original from that copy when you save it. SXEmacs also is capable of doing file system manipulations like creating and removing directories and files. The FTP interface is provided by the standard ‘efs’ package (efs)EFS. The ssh/rsh interface is provided by the optional ‘tramp’ package (tramp)TRAMP.