Edit Blog Links & Breadcrumb?
I had similar, work to be done, in drupal 7.

So, what I did, is, I collected the breadcrumb title, like this,

$bread = drupal_get_breadcrumb();
$title = $bread[0];

$lastCharacter = substr($title, -1);


$lastCharacter gave whether the breadcrumb title ends in S or not. If it ended, then, I appended, (')at last otherwise, I apended, ('s).I did this by adding a function in template.php file. Also, you can do by making any module, or any other way you wish.