BuddyPress restrict access to others profiles

At a BuddyPress website I have, I wish to have a system in place where for example:

Level 1 members can see and maintain their own profiles only. (No access to others profiles)
Level 2 members can see others profiles too.

Anyone kindly give a hint / idea to achieve the above.

Thank you very much

Can someone have a look here :

http://www.s2member.com/forums/topic/uri-restriction-for-buddypress-profile/

and please guide me where to put the second bit of code:

$displayed_username = str_replace("/members/", "", $_SERVER["REQUEST_URI);
$slash = strpos($displayed_username, "/");
$displayed_username = substr_replace($displayed_username, "", $slash);

Thank you

Mr Wells, @houfton can you kindly help me with this please?