MS Publisher 2007, How do I synchronize text boxes?

In MS Publisher I’d like to link 2 text boxes so that they mirror one another. For example, if I type “ABCDEF” in text box 1, I want “ABCDEF” to show up in text box 2 as well.
I know this function exists because in one of the templates there is a title box that repeats on every page, and each box updates to reflect the text changes you make to any single box.

Any help would be much appreciated, thanks.