Index External Site

Is it possible to have the ajax pro search index a webpage external to the site that it is installed on? I have a client that is migrating a website that has 30 years (12,000) of articles and PDFs that they call the archive. We are going to migrate that over to the new site, but it will take a while and we would like our readers to search on the NEW site for articles, then get a link to the archive of the old site.

We will remove this once all of the articles have been moved, but we are hoping that we can build another search bar on the new wordpress site, and have it index the old cold fusion site.