A hack for all pingbacks

As I understand it, WP by default only allows the first pingback from a given site or page and ignores the rest. I presume this is to reduce spam. However, I want to have extensive internal links on my site so people can easily get to related content and thought I could use the pingback for this purpose because it was automatic. However, there are often more than one link on a page, so the default set up will not work for me.

My search shows that this is controlled by wp-trackback.php. Near the bottom of this file is the following piece of code:

$dupe = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = '$comment_post_ID' AND comment_author_url =
'$comment_author_url'");
	if ( $dupe )
		trackback_response(1, 'We already have a ping from that URI for this post.');

So, can I delete or comment out this portion and solve my problem?

If so, am I setting myself up for spam problems?

Is there another workaround, like setting comment author url to accept from my site but not from others?

I found a plugin called moderate pingback but it hasn’t been updated since 2008. I wrote to the author but have not heard back. I went ahead and installed it but it did not work retroactively to add the missing pingbacks and does not alter the status quo for new posts, so it does not work now even if it did work in 2008.