$re = '/(?:UniquePrefixA|UniqueB|UniqueC)\s*(\[some-token\])(?:and|\s)*(\[some-token\])?(\s|[^\[\]])*(\[some-token\])?(\s|[^\[\]])*(\[some-token\])?(\s|[^\[\]])*/i';
$str = 'Examples 1-3:
[1] UniquePrefixA [some-token] and [some-token] want to take [some-token] to see some monkeys.
[2] UniqueC [some-token] wants to take [some-token] to the store. UniqueB, [some-token] is in the pattern once more.
[3] UniquePrefixA [some-token] is using [some-token] to [some-token].
';
preg_match_all($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