Does MC's 'Library Sync' option perhaps have any relevance to my requirement?
The synch option is limited as to what it synchs,
"What Is Not Synced- View customization (columns, sorting, adding / removing views) , Playlist deletion, Options changes (each client maintains its own options)".
Initially what worked for me was to create a new shared JRiver Library on an external drive.Everything lived on the drive including media, library itself, JRiver files,thumbnails, even MC backups of librrary.There are options within MC to relocate where files are located and other tricks to change default locations. You then just plug the external drive in to one or other pc and changes made in one will be reflected in other.You are literally not synching machines but rather sharing the same library and media on the same external drive ( small sized 1TB mobile drive).You then image or back up that drive to safeguard against loss of data. I have a different setup now but that worked well for me at the time. I can paste a tutorial of what I did if interested but someone would need to inform me how to place embedded screen shots so they can be interspersed between text explanations.
Obviously I didnt need streaming servers in that arrangement but I see no reason that media server should not be enabled and used (but others may ?)