edorsan on "users on different databases shared on a same root, for single login - register"

Dear Bemdesign, thanks for your reply ... :D
I have already tried multisite, but as I have a huge DB, it caused some problems. So I am trying to keep databases separatly, but still wanna share users data . I also have read the link you sended already, but I think it requires the databases to be under the same mysql folder, with different prefixes. Which is not my case... Maybe someone else can give me some ideas on that? Any suggestions? Thanks to all of you, in advance :)