Google-search – How to restrict the Google Search’s results to n number of sites? (n>1)

I sometimes want to do exactly that, and then I just add the word "stackoverflow" to my search string. This works wonders. Observe:

• beer stackoverflow
• clothing stackoverflow
• beautiful sunset stackoverflow

You can do that using the advanced search options: http://www.googleguide.com/sharpening_queries.html

I also found this, which might work for you: http://www.searchenginejournal.com/how-to-see-google-search-results-for-other-locations/25203/