[Zope] Extra Fancy Template Manipulation

Hi all, I've got three subsites that formerly used three different templates. I'd like for them now to use the same template, but I'd prefer not to have to touch the thousands of pages of content that currently point in three different places for their template. The easy solution is to copy/paste the template to three different places. But I don't like that solution. It will be obnoxious in the long run. I've never tried to manipulate templates and the execution of said templates with Python. Is there something I can do here to pass calls for the templates back to one place rather than actually duplicating my template? Cheers, Ed