Joomla: Get available values for a fieldsattach multiple selector

sample.php

<?php 
$db = JFactory::getDbo();

// Get the available offices
$offices = array();
$officeFieldId = 5;

$query = $db->getQuery(true)
	->select('field.extras')
	->from('#__fieldsattach AS field')
	->where('field.id = ' . (int) $officeFieldId);

$db->setQuery($query);

$officesData = $db->loadResult();

if ($officesData)
{
	$officesData = explode(chr(13), $officesData);

	foreach ($officesData as $officeData)
	{
		$officeData = explode('|', $officeData);

		if (count($officeData) != 2)
		{
			continue;
		}

		$offices[] = (object) array(
			'alias' => trim($officeData[1]),
			'name' => trim($officeData[0])
		);
	}
}