A family of Microsoft word processing software products for creating web, email, and print documents.
There is no way to do it with a field code, which has no way to know where the clicked hyperlink was.
But Word does have a way to behave exactly like a browser: Press Alt+left arrow (the "Back" shortcut in IE, Firefox, etc.), or customize the Quick Access Toolbar to add the Back button (which is in the All Commands category).
An alternative would be to make the target bookmark cover another hyperlink that points back to the first hyperlink (which needs its own bookmark).
Jay Freedman
MS Word MVP FAQ: http://word.mvps.org