lorax - 3:43 am on Jul 10, 2013 (gmt 0)
Welcome to WebmasterWorld Brian!
What you're really asking for is the noindex directive [google.com].
The noindex directive tells the bots not to index the content of the webpage you use the directive on - so in a sense, you can tell the bots to ignore the pages that are duplicated on one of your sites. This will avoid the duplicate content issue.