Possible to specify multiple sites to search using Bing

If I want to search the site mysite.com on Bing, I can type:

my search terms site:mysite.com

Is there a way to specify multiple sites to search? I've tried:

my search terms site:mysite.com,othersite.com

and

my search terms site:mysite.com site:othersite.com

but neither worked. Can it be done?