I just figured it out. Here is what I did for those of you who want to do the same thing...
- Opened search.php
- Added at the beginning of file: <?PHP $urls = $_SERVER['HTTP_HOST']; ?>
- Found the script: $search_results = get_search_results($query, $start, $category, $type, $results, $domains);
- Replaced it with: $search_results = get_search_results($query, $start, $category, $type, $results, $urls);
That's it! Now it is only pulling in the results for that single domain. Hope someone else finds this useful.