Thank you for your post.
There are multiple ways to share the same address book, they are described in this section
. So long as you are already using the Server, then the best way to sync the book will be through the server. I highly recommend then that you start using the 6.5 beta version (downloadable here
), because in this beta the entire sync mechanism and security model has been changed and vastly improved as compared with the current stable version and previous versions.
Don't hesitate to ask me if you have other questions.