Player Bob logs on to Go Fish on server A, then saves. He then logs on to Go Fish on server B, and saves.

The problem here is that two different saves are created. How can I allow other users to host my game so that it will be open more, but the characters move between servers. Is this possibe?
You have to have a central server to store the savefiles on, otherwise it can't be done. If you have a server, then anyone can access their savefiles from the server.