Merge Emails (like you can merge leads)

Marketo should allow you to be able to merge emails so the same email ID is carried over to emails that already exist in a nurturing stream. For example, if you have a new email template and want to update your emails with the new template's looks, you should be able to create the new email and merge it with the old email so that it picks it up as the same email within your nurturing stream and isn't viewed as a completely new email.