Turning nested lists into one list using wp_list_pages

I have the following list using the wp_list_pages function:

<ul>     <?php wp_list_pages('include=27,29,23,21,1614&title_li='); ?> </ul> 

However, pages 23, 21 and 1614 are all child pages of page 29.

So the code that is output includes a nested .children list

Is there a way I can include each of these pages in just one list? I’ve tried modifying the depth parameter but it doesn’t give the result that Im looking for.