Can we add additional pages to the Sitefinity search index?

Is it possible to add pages outside of Sitefinity into the search index? We have some non-Sitefinity pages that are part of our site that we would like to have show up in our search results.

FWIW,

I have added a couple of extra sites we have into the sitemap by creating a page that redirects to the external site.  Sitefinity has picked up the external pages content and it shows up in a search in Sitefinity in the description.  I now that may now help you getting a complete site indexed, but it does show there is some capability to index an external sites pages.

Anthony