Different sidebars in different pages and subpages

I think I’m close on this but…

I’m trying to get 4 pages that need different sidebars to appear at the main sidebar for that page(1,2,3,4). Each of those 4 pages have child pages under them. The child pages need to have the same sidebar as the parent pages.

In our pages.php file we have

<?php

if (is_page('28') && $post->post_parent =="28") {
	include ('sidebar-1.php');
} elseif (is_page('36') && $post->post_parent =="36") {
	include ('sidebar-2.php');
}  elseif (is_page('38') && $post->post_parent =="38") {
	include ('sidebar-3.php');
}  elseif (is_page('24') && $post->post_parent =="24") {
	include ('sidebar-4.php');
}
	else{
	include ('sidebar.php');
	}
?>

I’m stuck in getting the parent pages to show the correct sidebar, however the child pages do show them correctly.

Any ideas?