Solution - 1

You need to use WP_Query. Something like this:

global $post;

// this gets the term(s) for the subdivison tax for the current post
if( $terms = wp_get_object_terms($post->ID, 'subdivision') ) {

// Use the first one (you could use more) to get other posts:
$args = array(
'post__not_in' => $post->ID, // we don't want the current post!!
	'tax_query' => array(
		array(
			'taxonomy' => 'subdivision',
			'field' => 'slug',
			'terms' => $terms[0]->slug
		)
	)
);
$query = new WP_Query( $args );

while($query->have_posts()):
      $the_query->the_post();

// Do whatever layout you want.
     echo '<li>';
     echo the_title();
     echo '</li>';
endwhile;
}

Solution - 2

there might be a better way to do this, but the easiest way that comes to mind is to do a custom sql query. First, you need to get the City of the current post:

$cities = get_the_terms(get_the_ID(),'city'); 
//and we'll get the subdivision so we can exclude it later:
$subdivisions = get_the_terms(get_the_ID(),'subdivision'); 

if ( $cities && ! is_wp_error( $cities ) ) : 
$city_id='';
	foreach ( $cities as $city ) {
		$city_id = $city->term_id;
	}
		if ( $cities && ! is_wp_error( $cities ) ) : 
$subdivision_id='';
	foreach ( $subdivs as $subdiv ) {
		$current_subdiv_id = $subdiv->term_id;
	}				
endif;

global $wpdb;
$subdivs=$wpdb->get_col( 
	$wpdb->prepare( 
"select distinct(t.term_id) from $wpdb->terms t
join $wpdb->term_taxonomy tt on tt.term_id = t.term_id
join $wpdb->term_relationships tr on tt.term_taxonomy_id = tr.term_taxonomy_id
join
(select id from $wpdb->posts p
join $wpdb->term_relationships tr on p.id = object_id
join $wpdb->term_taxonomy tt on tt.term_taxonomy_id = tr.term_taxonomy_id
where tt.term_id = $city) p on p.id=tr.object_id
where tt.taxonomy = 'subdivision'
and t.term_id<>$current_subdiv_id
limit 5"
));
$subdiv_links = Array();
foreach($subdivs as $subdiv_id){
$subdiv=get_term_by('id',$subdiv_id,'subdivision');
$subdiv_links[]='<a rel="nofollow" href="'.get_term_link($subdiv->slug, 'subdivision').'">'.$subdiv->name.'</a>';
}

Solution - 3

try this define this in functions.php

function tax_related_posts($taxonomy = '') {
	
	global $post;
	
	if($taxonomy == '') { $taxonomy = 'post_tag'; }
	
	$tags = wp_get_post_terms($post->ID, $taxonomy);

	if ($tags) {
		$first_tag 	= $tags[0]->term_id;
		$second_tag = $tags[1]->term_id;
		$third_tag 	= $tags[2]->term_id;
		$args = array(
			'post_type' => get_post_type($post->ID),
			'posts_per_page' => 4,
			'tax_query' => array(
				'relation' => 'OR',
				array(
					'taxonomy' => $taxonomy,
					'terms' => $second_tag,
					'field' => 'id',
					'operator' => 'IN',
				),
				array(
					'taxonomy' => $taxonomy,
					'terms' => $first_tag,
					'field' => 'id',
					'operator' => 'IN',
				),
				array(
					'taxonomy' => $taxonomy,
					'terms' => $third_tag,
					'field' => 'id',
					'operator' => 'IN',
				)
			)
		);
		$related = get_posts($args);
		$i = 0;
		if( $related ) {
			global $post;
			$temp_post = $post;
				foreach($related as $post) : setup_postdata($post);
					$content .= '<ul class="related-posts-box">';
						$content .= '<li><a rel="nofollow" href="' . get_permalink() . '" title="' . get_the_title() . '">' . get_the_title() . '</a></li>';
					$content .= '</ul>';
					
				endforeach;
			$post = $temp_post;
		}
	}

	return $content;
}