Private Card

[KylieHannaford]

Does anybody know if it is possible to create a card that is only visible via a particular login? I'm a designer, and my client wants to have a branded online Christmas card for their staff to personalise with a greeting and send out to their contacts like this service offers. Is it possible for us to design a card for them, then upload it into the database, however make it a private link/card so that only their staff are able to access it?