Expression To Perform A Model Rule

Hi,

is there a way to apply a rule on Model by condition?
I mean something like that

public function rules() {
    array('specialattribute', 'numerical', 'integerOnly' => true, 
'when'=>'Yii::app()->user->checkAccess("superadmin") or a method'),
}

instead of

public function rules() {
    array('specialattribute', 'numerical', 'integerOnly' => true, 
'on'=>'superadmin'),
}

to avoid the repeateding set of scenario in Controllers/action

if there is no way yet, may be included in yii 2