Although it’s a better practice to merge all your JS files in a single JavaScript and enqueue it to reduce HTTP requests, it’s alright to enqueue them separately too. So, you can register the script ( not required ) and then enqueue it.
Just enqueue all of the scripts after registering them, like:
// Template ABC
if ( is_page_template( array('template-1.php','template-2.php'))):
wp_register_script( 'Name of JS File', 'https://url.js' );
wp_register_script( 'Name of NEW JS File 1', 'https://url-new-1.js' );
wp_register_script( 'Name of NEW JS File 2', 'https://url-new-2.js' );
wp_enqueue_script('Name of JS File');
wp_enqueue_script('Name of JS File 1');
wp_enqueue_script('Name of JS File 2');
endif;
Or directly enqueue them all:
// Template ABC
if ( is_page_template( array('template-1.php','template-2.php'))):
wp_enqueue_script( 'Name of JS File', 'https://url.js' );
wp_enqueue_script( 'Name of NEW JS File 1', 'https://url-new-1.js' );
wp_enqueue_script( 'Name of NEW JS File 2', 'https://url-new-2.js' );
endif;