Ticket 11394 adds the merge! method to any ActiveRecord::Errors object. If anyone has time to review the ticket and post their comments on if they like the idea of having this functionality (and/or +1 or -1 if you are able take a few minutes and verify the patch):
http://dev.rubyonrails.org/ticket/11394
Examples: person.errors.merge! address.errors person.errors.merge! address.errors, :only => [ :city, ;state ] person.errors.merge! address.errors, :except => [ :street, :zip ]
Thanks,
Zach Dennis http://www.continuousthinking.com