$re = '/object\/(custom|standard)\/(.*)(?:\/(typea|typeb))(?:\/(.*))?/m';
$str = 'Objects/Custom Objects/Applicant/Recruitment Pipeline/Buttons, Links, and Actions/Accept
object/custom/name1/name2
object/custom/name1/name2/typea
object/custom/name1/name2/typea/item
object/standard/name1/name2
object/standard/name1/name2/typeb
object/standard/name1/name2/typeb/item';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php