Hi Leah,
It is not possible to use different databases unless you use different installations of mojoPortal for each site.
Personally I never create content in a database on my local machine and then restore it on production. I create all content including new sites on production and periodically I get a backup from production and restore it on my test environment.
If I'm concerned about users seeing the content then I just make the pages only visible to Admins role, and when I'm ready to publish a page I change the view roles to allow All Users.
Sometimes I might also use a temporary host name until I'm ready to make it live, like dev1.mydomain.com, not that this hides the pages but unless someone knows about that host name it is not likely that people will stumble on it. As I said before if I want to be sure no-one can see it until I'm ready I use view permissions to protect the page.
Hope it helps,
Joe