gistfile1.txt

$parent = '/processwire/access/users/' . $user->name;
foreach($pages->get("/tools/categories/")->children("sort=title") as $tag) {
    echo "<h2>$tag->title</h2>";
    foreach($pages->find("parent={$parent}, course_categories=$tag") as $p){
         echo "<a href='{$p->course_documents->url}'>{$p->course_documents->name}</a>";
    }
}