function my_module_views_pre_render(&$view){
  if ($view->name == 'group_booking'){
    foreach($view->result as $r => &$result) {
      $dates[] = $view->result[$r]->field_field_date[0]['raw']['value'];
    }
  }
  return $dates;
}


function my_module_form_commerce_cart_add_to_cart_form_alter(&$form, &$form_state, $form_id) {
  dpm(my_module_views_pre_render());
}