forget about hiding the linked server...just make sure only specific users are mapped to use credentials that are valid on the linked server, so everyone ELSE is "not be made",
the list of linked servers is available under the public role, i believe, but just because something exists, doesn't mean end users can use it.
to resolve your job issue what you want to do is have a job run under a specific users permissions that DOES have access to the linked server.
Lowell