是否有一个函数在PHP中组合这些数组？

Given arrays 'a1' and 'b1' how may they be combined them to produce the final array? Basically replacing the value within 'a1' with the array data for the matching value within 'b1'. I guess the question would be if there is a function that can do this that I'm not seeing.

$a1 = array('id1'=>array('a'=>'444-444',
                         'b'=>'222-222',
                         'c'=>'111-111'),
            'id2'=>array('a'=>'888-888',
                         'b'=>'666-666',
                         'c'=>'555-555')
           );

$b1 = array('222-222'=>array('first'=>array('9999',
                                            'dddd',
                                            'yyyy'),
                             'second'=>'mmgghh'
                            ),
            '666-666'=>array('first'=>array('bbbb',
                                            'cccc',
                                            '7777'),
                             'second'=>'ffffgggg'
                            )
           );

Desired combination:

array(2) {
  ["id1"]=>
  array(3) {
    ["a"]=>
    string(7) "444-444"
    ["b"]=>
    array(1) {
      ["222-222"]=>
      array(2) {
        ["first"]=>
        array(3) {
          [0]=>
          string(4) "9999"
          [1]=>
          string(4) "dddd"
          [2]=>
          string(4) "yyyy"
        }
        ["second"]=>
        string(6) "mmgghh"
      }
    }
    ["c"]=>
    string(7) "111-111"
  }
  ["id2"]=>
  array(3) {
    ["a"]=>
    string(7) "888-888"
    ["b"]=>
    array(1) {
      ["666-666"]=>
      array(2) {
        ["first"]=>
        array(3) {
          [0]=>
          string(4) "bbbb"
          [1]=>
          string(4) "cccc"
          [2]=>
          string(4) "7777"
        }
        ["second"]=>
        string(6) "ffffgggg"
      }
    }
    ["c"]=>
    string(7) "555-555"
  }
}

array_walk_recursive($a1,function(&$value,$key,$addin){
        if(is_scalar($value) && isset($addin[$value])){
                $value = array($value=>$addin[$value]);
        }
   },$b1);