Rustaurius on "Modify Title Within Shortcode Function"

Hi,

I'm looking to potentially modify the page title within a shortcode, depending on a saved setting. I can't get my head around what I should be calling. Here's what I've tried so far:

if ($Filter_Title == "Yes") {
  add_filter('the_title', 'Alter_Title', 20, $ProductName);
}

Those lines are within a shortcode that is working normally. The code doesn't seem to work, so any thoughts on where/how I should be adding the call to the filtering function would be appreciated!