I'd like to set an autoresponder campaign up once, but have the same campaign sent to 3 lists. Is there any way to tell it to send to all 3 without having to create all the emails in the campaign 3 times?
You can simply duplicate the same campaign using the COPY functionality. Do not use the merge lists feature. In 2.x we improved this, but till then, best is to copy the campaign over and avoid merging lists.