Not for the faint-hearted...Groups/logins and iframes

Are you familiar with Iframes/usergroups for Joomla?

My site is Joomla.I need some help from an php expert please!!!

Im way over my head , been trying to figure a solution. In short this is how the site works and what I have to have implemented.

****In the index.php file a friend added this code to hide the homepage from the users/groups CT, this has to change someway to be hidden from ALL my groups (Groups= CT and XL) everyone except for Registered.(So all these groups shouldnt see the homepage or the : Top Places Travel pag.
They should also be able to navigate back to their landingpage which it doesnt allow for now…) This is my biggest obstacle.

See the code shows that the groups have the “dealermenu” and the Registerd users have the mymainmenu.(Allthough I need to find a way to create for EACH group their own landingpage.)

<?php
// Get the user object
$user = &JFactory::getUser();
// Now work out the User ID
$userType = $user->get('usertype');
// hide the module if user is not logged in
if ($userType == "CT") :
  // Now we break out of the PHP tags and display the JDOC tag to include the module
?>

  <div id="topmenu">
    <jdoc:include type="modules" name="dealermenu"  style="xhtml" />
  </div>
<?php else: ?>
  <div id="topmenu">
    <jdoc:include type="modules" name="mymainmenu"  style="xhtml" />
  </div>
<?php endif; ?>

<snip/>
The site has 2 logins (one for Registered users - then all the other landingpages created for each group/client.

In the database(MySQL) I have inserted : CT and XL(new groups)

topplacestravel.co.za is logged in for Registered users

Our Aim:
We create landingpages for clients on our website with there own logo such as
topplacestravel.co.za/test-ct and
topplacestravel.co.za/test-xl
(You wont be able to log in)

These groups(there will be more) will only log into the site via this url. They will use it as a Iframe.
They must not see the homepage <snip/>
They will all need there own landingpages with logos. The rest of the pages will all be EXACTLY the same for all the groups.

Can ANYONE help?:sick: