I found a solution. I just set my own value for the “post_date” field in the wp_insert_post function.
As an example:
$time = time();
for ($i=0; $i < count($postArgs); $i++) {
$postArg = $postArgs[$i];
$postArg['post_date'] = $time-$i;
wp_insert_post($postArg);
}