Is it possible using nginx to essentially look at the http referer header, and if its set to a specific value, and the page is index.html or /, redirect to a custom landing page.

For example:

# Psuedo code
if($page = "index.html" and $http_referer ~* (www\.)?amazon.com.*) {
rewrite ^ "our-amazon-landing-page.html" permanent;
}