I know that multiple JVMs can share the same Registry on a server. The Registry is basically a hash map of arbitrary (but hopefully unique) object names to the TCP/IP socket server address of each instantiated Remote object. The Registry is sort of like DNS.
I don't see any technical reason why your cross-server idea shouldn't work. However, there are lots of security reasons why a multi-server Registry might be a bad idea. For example, I don't think the Remote object's name space is protected at all, so you might have a rogue process on another machine overwrite (rebind) over the top of your Remote object, causing some headaches. I'm a little surprised that Sun allowed multiple JVMs to share the Registry, for the same reason, but they did.
So, bottom line, it's probably not going to work.
If it's important, you could write your own Registry replacement… just a hashmap of
String names pointing to the Remote objects that registry with it. Your more liberal version of the registry could implement a getRemote(String name) method that returns Remote, and a bindRemote(String name, Remote remote) method that would accept calls from any server (using an RMI Registry on your main "lookup/directory" server.).