Site URL set, but doesn't display correctly

Ok, so I have one hosting account with one main domain (granitechristianacademy.org), and another site recently added under /FBC (gofbc.com). I set the Site Address setting to http://www.gofbc.com, but every time you visit it the address bar shows http://www.granitechristianacademy.org/FBC/pageID. I need the gofbc to display just gofbc.com/pageID and not the entire string with the academy domain. On my control panel for the hosting service I set the destination of granitechristianacademy.org to /, and the destination for gofbc.com to /FBC…does this have something to do with it? I even attempted a redirect through .htaccess and the page wouldn’t load due to too many redirects…how can I fix?

I appreciate any replies I can get!!!