Conditional display from hyperlink

I am looking for an elegant way to change some elements of my main template based on a hyperlink from a loop in a sidebar menu.

On http://howlingwolfmedia.com/site3/classes/class-categories/ expand the menus on the left. Currently the link from this sidebar goes directly to the permalink for the post e.g. http://howlingwolfmedia.com/site3/basic-step/ I want all pages displayed from this menu to use a title echoing the word ‘Classes’ instead of the default from the index page. And i want to continue using the sidebar-classes menu as on class-categories template.

I was thinking of something along these lines?
http://kovshenin.com/2012/sprintf-with-wordpress/