This is a simple module that builds on top of XML Sitemap module (v2.0). It allows generating sitemap.xml for multiple domains that point to the same Drupal site. For example, you might have example.com, example.us, example.io that all point to the same Drupal site. Using this module will allow generating separate sitemap.xml files under each domain that point to the correct domain name. For example, example.us/sitemap.xml will have links pointing to example.us/..., etc.