has and belongs to many - cakephp HABTM and dependency upon another foreign model -

i have resource habtm room. room model depends on model building. how can integrate dependency?

class resource extends appmodel {      public $hasandbelongstomany = array('room' =>         array(             'conditions' => array('room.building_id = building.id'),         )     ); }  class room extends appmodel {     public $belongsto = array('building');      public $hasandbelongstomany = array('resource');      public $virtualfields = array(         'name' => 'concat(building.short, room.floor, ".", room.number)'     ); 

in model , belongsto linking did way:

public function beforefind($query) {         parent::beforefind($query);          $this->bindmodel(array(             'belongsto' => array(                 'room' => array(                     'foreignkey' => false,                     'conditions' => array('booking.room_id = room.id')                 ),                 'building' => array(                     'foreignkey' => false,                     'conditions' => array('room.building_id = building.id')                 )             )         ));     } 

but have no clue how bind/add building model ressource model. have add resource model working?

thanks in advance!