Multiple Dropdown List

I’m using giix. I need to make this drop-down to allow multiple selects. Can anyone assist?

<label><?php echo GxHtml::encode($model->getRelationLabel(‘recruitColleges’)); ?></label>

	&lt;?php echo &#036;form-&gt;dropDownList(&#036;model, 'recruitColleges', GxHtml::encodeEx(


		GxHtml::listDataEx(


			College::model()-&gt;findAllAttributes(null, true)), false, true)); 

?>

Give the attributes of the Collage model, as




College::model()->findAllAttributes(null, true)), 'id', 'name'