Magento Load template in template : You can load template in template directly
as following.
Magento Load template in template
Mage::app()->getLayout()
->createBlock('core/template')
->setData('yourData',$yourData)
->setTemplate('yourTemplatePath/yourTemplateName.pthml')->toHtml();
You can get the data passed to your template “yourTemplateName.pthml” data as below:
$data = $this->getData('yourData');