oh i have made a menu with pages..
Then forget my ramblings about categories and hooks, and stick with pages and directly editing the template.
Can you set featured image to be a slideshow instead of a static pic?
Nope. Well, you can achieve the effect you want, but not by using the featured image functionality.
I have no idea how to do it
Make a few slideshows, one for each page. Also decide which one is to be the default - probably one that should go on your home page. As you're creating them, you'll be asked to provide a slug. Make a note of each one. In my code above, these slugs appear as "slideshow-slug-1" etc.
Make a few pages. The content can be blank for now, but you'll need to provide a title. Then WP will automatically create a slug, which appears below the Title field in the page editor. You can edit that slug if you want. Make a note of each one. In my code above, *these* slugs appear as "page-slug-1" etc.
Open headers.php. As I understand it, you've already put in a line there, to display a single slideshow. Delete that line, and paste the code above. Now modify the code, so that each
is_page() contains one of the page slugs you noted, and each meteor_slideshow() contains the appropriate slideshow slug to match that page. For the last pair of lines, the
else, put your default slideshow slug. If WP doesn't recognise which page it's on from the previous options, it'll show this one. Typically that might be the homepage, but it could also be any other page, such as pages added after you've finished the design.