I'm sure there is a way to do this but I can't figure it out. I want to display a post based on variables that I gather (from GET and $wpdb) rather than using a permalink - i.e. the same URL would produce a different post depending on the circumstances. Is there a way to do this such that I don't need to change a great deal of code in the displaying of the post (i.e. I can still use the standard .php files with the_title, the_content etc., but just with an added function somewhere to change the post which all the functions refer to)?
So I could display the posts the usual way (with permalinks), but also have another page which works out which post to show the viewer based on some internal logic rather than solely based on the URL?