add_layout_view_helper.php

<?php
class Zend_View_Helper_AddLayout {

    protected $_plugin;

    public function __construct() {
        $this->_getPlugin();
    }

    protected function _getPlugin() {
        $front = Zend_Controller_Front::getInstance();
        $pluginClass = 'My_Controller_Plugin_NestedLayout';
        $plugin = $front->getPlugin($pluginClass);
        if ($plugin) {
            $this->_plugin = $plugin;
            return;
        }
        $this->_plugin = new $pluginClass;

        Zend_Controller_Front::getInstance()->registerPlugin($this->_plugin);
    }

    public function addLayout($name) {
        $this->_plugin->addLayout($name);
    }
}
?>

nested_plugin_controller.php

<?php
class My_Controller_Plugin_NestedLayout extends Zend_Controller_Plugin_Abstract {

    protected $_layouts = array();
    protected $_layoutsAtPostDispatch = array();

    public function addLayout($layout) {
        $this->_layouts = array_merge(
            $this->_layouts,
            array_diff((array) $layout, $this->_layouts)
        );
    }

    protected function _renderLayouts() {
        $mvcLayout = Zend_Layout::getMvcInstance();
        $this->_layoutsAtPostDispatch = array_reverse($this->_layouts);

        $layout = clone $mvcLayout;
        foreach ($this->_layouts as $layoutName) {
            $layout->setLayout($layoutName);
            $layout->{$mvcLayout->getContentKey()} = $this->getResponse()->getBody();
            $this->getResponse()->setBody($layout->render());
        }

        $newLayouts = array_diff(
            $this->_layouts,
            $this->_layoutsAtPostDispatch
        );

        if (count($newLayouts) > 0) {
            $this->_layouts = array_diff(
                $this->_layouts,
                $this->_layoutsAtPostDispatch
            );
            $this->_renderLayouts();
        }
    }

    public function postDispatch() {
        $this->_renderLayouts();
    }

}
?>