My b2evolution Version: 3.x

Ok, I've struggled with this for a while and am going around in circles. I'm trying to make it so Intro-Main posts show on the front page of my blog and nothing else does. I've tried putting this code in my posts.main.php just above the Post Content section:

<?php
					// Go Grab the featured post: 
if( $Item = & get_featured_Item() ) 
{    // We have a featured/intro post to display: 
    // ---------------------- ITEM BLOCK INCLUDED HERE ------------------------ 
    
    // ----------------------------END ITEM BLOCK  ---------------------------- 
     

    // The code below hides other posts and navigation pages from home page 
    if( $Item->ptyp_ID == 1500 ) $GLOBALS['MainList'] = NULL; 
} 
?>

And that works - ALMOST. It messes up my category pages with normal posts. The front page looks pretty good, but nothing else does. What am I missing?