In the navbar template, find every instance of (only one instance in a default template):
HTML Code:
<td class="vbmenu_control"><a rel="help" href="faq.php$session[sessionurl_q]" accesskey="5">$vbphrase[faq]</a></td>
And change to this:
HTML Code:
<if condition="is_member_of($bbuserinfo,x,y,z)">
<td class="vbmenu_control"><a rel="help" href="faq.php$session[sessionurl_q]" accesskey="5">$vbphrase[faq]</a></td>
</if>