Hide/Remove a site page from WP / BP Navigation in Social theme

Well I’v added Page-A and Page-B to my WordPress-Buddypress (theme Social). Page B has a form which is submitted to Page-C (page-c.php). I want the first two pages to be visible in the navigation. But I don’t want the third one (Page-C) to be visible in the Navigation bar. How to get a list of main Navigation members, Then other sub navigation arrays (if any page has sub-pages)? Please advise