I agree with Andrew that this is better handled using building blocks, specifically AutoText.
Automated Boilerplate Using Microsoft Word



You can keep all of your alternatives in a single template and if you want can use a building block gallery content control to allow easy switching.

You can, if you want, also have several different templates with different content and the same name. By changing which one is loaded as a Global Template you can change the content of the documents involved. Your content would be inserted automatically into your documents using AutoText fields.