Targeting specific instane of wp_list_pages

Simply add the filter before the call and remove it afterward something like this

<ul id="headerlinks"> 
<?php 
 add_filter('wp_list_pages', 'add_markup_pages'); 
wp_list_pages('title_li=&include=24,26,28,30'); 
 remove_filter('wp_list_pages', 'add_markup_pages'); 
?> </ul>

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