I know that in Magento 1.4.2.0 one gets parent id\'s like so
list( $parentId ) = Mage::getModel(\'catalog/product_type_configurable\')
You can just call both and offer a fall-back as it should be one or the other:
if($product->getTypeId() == "simple"){
$parentIds = Mage::getModel('catalog/product_type_grouped')->getParentIdsByChild($product->getId());
if(!$parentIds)
$parentIds = Mage::getModel('catalog/product_type_configurable')->getParentIdsByChild($product->getId());
if(isset($parentIds[0])){
$parent = Mage::getModel('catalog/product')->load($parentIds[0]);
// do stuff here
}
}