Different sidebars for different templates

I am a bit stucked. I want to display different sidebars for different (page) templates. I have about 15 different page templates and would need at least 10 different sidebars. They are all made, but they will be added upon my existing sidebar, a sidebar which is called in every template file AND in header.php.
Do I have to declare something in my functions.php? Like
if pagetemplate_x then sidebar_10…or..?