How to get and pass the selected value to the tab controller in magento 1.9 admin?


Now I am creating a module for magento admin page.Below is the screenshot

What I want to do is if I select "Template" in Dynamic block i want to get that option value and pass that value to the next "Text and images" tab(tab controller)

I don't know how to get that value and pass value to tab controller.
Here is some example code I want to pass the value in URL

$this->addTab(   'dynamicpages'   array(   'label' => Mage::helper('agile_dynamicproductpage')->__('Text and Images')