You could use Custom Post Types which will keep users from selecting a custom template.
Here are a few links to help you get started:
Plug-ins:
For More Control you might use Custom Taxonomies (WordPress Codex Page):
The options mentioned above would require assigning existing posts that need to be added to the archives to the custom post types.
Another solution might be, adding a custom file that holds the code for the archives page. You could then use a conditional statement to call the file automatically if the posts meet the criteria you specify in the new file code. For example, you could create an archive called custom_archives.php (no custom template header required since you’ll use get_template_part('custom_archives'); to call the file). Then in your index.php file or whichever is calling the posts you could use something like:
<?php if(is_category( 'commercials' ) ) {
get_template_part('custom_archives');
?>
<?php
} else {
// your regular archives code...
} ?>
As you can see there is more than one option. It’s hard to be more specific without knowing the full scope of your project, but one of the methods above should work. If you have questions I’ll try to help.