If you're willing to code, you can do anything you want in Word.
The Word object is very programmable.
You still get vba script too, so ... what conditions?
Here's a bad example
http://stackoverflow.com/questions/3958105/how-to-apply-colour-formatting-to-a-richtextbox-as-the-user-types-vb-net
but within the document, you can add vba and reference itself
once you get a handle on the word doc, you can walk through the text and do stuff to it
http://www.ehow.com/how_7267196_use-vba-macro-change-fonts.html
getting started with vba in word 2010
http://msdn.microsoft.com/en-us/library/office/ff604039%28v=office.14%29.aspx