how tell search engines the content on the page should be credited to another we

[petebolduc]

I have been tasked with creating an archive sub-domain site for an organization that will have content in the archive that is actually live on the organization's main site at the same time.

Because the organization wants the archive open to the public search engines will be able to index its pages. How do I inform the search engine that the content on the archived page should be accredited to the main site?