<?php
$str = "Foo Bar (Any Group - ANY GROUP Baz)";
$replacement = "$1$2";
print preg_replace("/\b([\w'-]+)(\s+\\1\\2)+/i", $replacement, $str);
?>
PD9waHAKCiRzdHIgPSAiRm9vIEJhciAoQW55IEdyb3VwIC0gQU5ZIEdST1VQIEJheikiOyAKJHJlcGxhY2VtZW50ID0gIiQxJDIiOyAKcHJpbnQgcHJlZ19yZXBsYWNlKCIvXGIoW1x3Jy1dKykoXHMrXFwxXFwyKSsvaSIsICRyZXBsYWNlbWVudCwgJHN0cik7Cgo/Pg==