Yes, there is probably a way to do this but it is going to be theme/plugin dependent. Without knowing the details I don’t think a good answer is possible. However, there are a couple of general case solutions.
The first is to add your callback on a hook that runs after the breadcrumb code.
function subtitleCategory ($title) {
return $title."</div></div></div><div class=\"container_24\"><h2 id=\"category-subtitle\">TEST1</h2></div>";
}
function hook_in_after_breadcrumb($qry) {
add_filter('single_cat_title', 'subtitleCategory');
}
add_action('some_hook','hook_in_after_breadcrumb');
I don’t know what some_hook
should be as that is theme/plugin dependent.
You could count your instances that the filter fires and target one:
function subtitleCategory ($title) {
static $c = 0;
$c++;
if (2 === $c) {
return $title."</div></div></div><div class=\"container_24\"><h2 id=\"category-subtitle\">TEST1</h2></div>";
}
}
add_filter('single_cat_title', 'subtitleCategory');
A change of theme or a plugin could break that somewhat cludgy, manual solution though.