public function setup_cache_groups() {

		// Global groups.
		wp_cache_add_global_groups( array(
			'bp_friends_requests',
			'bp_friends_friendships', // Individual friendship objects are cached here by ID.
			'bp_friends_friendships_for_user' // All friendship IDs for a single user.
		) );

		parent::setup_cache_groups();
	}