wp_insert_post - How do I prevent incremental numbers on child pages?

Question

I'm using wp_insert_post to dynamically generate child pages for a given page using a predefined array of values. The goal is to give each child page the same slug.

For example, clicking "Generate Pages" on "example-page" loops through wp_insert_post and creates two child pages:

/example-page/about
/example-page/contact

The trouble is that WordPress is adding numbers after the slug on the child pages (because similar child pages have already been created for a different page).

My guess is that it's doing a check on slug availability irrespective of the parent/child relationship.

I've experimented with trying to run wp_update_post after the insertion but to no avail.

Any ideas?

UPDATE

Here's a code sample:

$new_page = array(
    'post_title' => $child_page["title"],
    'post_parent' => $parent_id,
    'post_name' => $child_page["slug"], 
    'post_content' => $child_page["content"],
    'post_status' => 'publish',
    'post_type' => 'territory'
); 

$new_page_id = wp_insert_post($new_page);

Explanation: I am looping through an array of $child_pages, in which I've set the unique values for title, slug, and content.