Send multiple files with one PHP, not at the same time - php

Question

Not sure how to word my question, but this is it:
I have an XML with 1000 products that I need to upload. I can only upload 100 products at a time with PHP. How do I make one PHP upload 100 products at a time until all products are uploaded?
Currently, my solution is to have 10 PHP files and 10 XML files each with 100 products. I would prefer if I can do this with 1 XML and 1 PHP file.
The reason I cannot do more than 100 products is that the sever I am uploading to doesn't allow me to more than 100 per instance.
I am using simplexml_load_file to load the files in the PHP
This is my code so far:
<?php
$data = Array();
$xml=simplexml_load_file("products_1.xml") or die("Error: Cannot create object");
foreach ($xml->product as $pr) {
$data[] = Array
(
"id" => (int)$pr->identifier,
"name" => (string)$pr->name,
...
);
}
// username & password
#$data = array_slice($data, 1,10);
#$data = $data[20];
$username = '...';
$password = '...';
//create hash
$hash = base64_encode($username . ':' . $password);
$headers = array(
'Authorization: Basic ' . $hash
);
// send data with cUrl
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://.../api/product/save');
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array('data'=>($data))));
$result = curl_exec($ch);
// decode response
$all=json_decode($result);
// print array response
echo '<hr>';
echo '<pre>';
print_r($all);
echo '</pre>';
//echo '<hr>';
?>
For the other PHP files, I just replace the products_1.xml with the next number