Menu shortcode

[shortmenu menu=”tad” display=”inline” enhance=”true” ]
(tad is my menu name)
this is how my products menu arranged
products>
-category 1
-category 2
-category 3
-sub category 1
-sub category 2
I wanted to show all menu items ( product categories) under product menu to be shown in the product page horizontally
I was able to do that by creating a new menu and again creating all menu items from the original product menu, then using a menu short code (which was generated through shortcode menu plugin) in the product page

now the problem is everytime when i add a new category under product menu I need add that category again in my new menu is there any workaround for this? perhaps a similar shor code which shows sub menu items from one of the main menu item so i don’t have to make new menu at all