Change hidden field value based on custom validation

I created a custom validation method for a field with the gform_validation filter.
Is it possible to store some data in a hidden field inside the gform_validation filter?

add_filter('gform_validation', 'media_custom_validation');

function media_custom_validation($validation_result) {

 	global $form_email, $file_id;

	// new gravity form
	$rg = new RGFormsModel(); 

 	// grab the form
        $form = $validation_result["form"];

 	// only validate the vault form
  	if ($form['title'] == "Item Support") {

		foreach($form['fields'] as &$field) {

			// store email field in variable
			if ($field['id'] == "5") {
						if(true){
							//success, store data in one of the hidden fields
						} else {

							//error
						}
				}

			}

		}
	}
    return $validation_result;
}