How to ONLY display a specific assigned category when a post is assigned to more than one

I have some posts assigned to more than one category. The loop I'm using is only for specific categories. But I need to display the assigned category name. When there's a post that fits into my loop because it's assigned one of the categories I'm using, but it is also assigned to one that's not, I need to only display the category name for the loop I'm currently using.

So, let's say I have a post assigned to "properties", and "featured". I only want to show posts assigned to "properties" (and several others). I have this code:

$args = array(
   'post_status' => 'publish',
   'cat' => array(32,31,34,33),
   'orderby' => 'date',
   'order' => 'DESC',
);

$the_query = new WP_Query($args);

if ( $the_query->have_posts() ) {
   while ( $the_query->have_posts() ) {
      $the_query->the_post();

      $cats = get_the_category();
      $cat_slug = '';
      if ( ! empty( $cats ) ) {
         foreach ( $cats as $cat ) {
            $cat_slug .= $cat->slug . ' ';
         }
      }
      echo $cat_slug;
   }
}

It shows all category names

And when I use

the_category(', ');

It shows all categories and links (which I would expect for that one).

I need to NOT display the category name that's not part of the current loop.