testa

<?php
$array= Array
(
    "RT III" => 3,
    "RT II" => 2,
    "RT I" => 2,
    "RT V" => 1,
    "RT IV" => 1,
    "RT IX" => 4,
    "RT X" => 4,
    "RT XI" => 5,
);



foreach($array as $key=>$val){
        $data2[$val][] = $key;

}
krsort($data2);


    foreach($data2 as $ar2){
    $ar3=array();
    foreach($ar2 as $i=>$v){
            if($i>=1) {
            $ar3[]=$v ;
              echo implode(', ',$ar3),"2<br />";
              $stop=1;
              break;
            }
        $ar3[]=$v ;
    }
    if(isset($stop))break;
    echo implode(', ',$ar3),"<br />";
    }
/*
RT XI
RT IX, RT X2
*/