Dan:
Not easily - that is to say that there isn't some switch you can turn on the make master pages behave differently. The browser doesn't know there is a master page and a content page - it only sees HTML for a single page. When the browser navigates somewhere new, it reloads the entire page. (See also http://odetocode.com/Blogs/scott/archive/2006/06/30/4743.aspx).
If you want the page to perform differently, look at using AJAX or frames.