If you have an account on fiverr with "extra" enabled, than this question for you.
Can you set "This item requires shipping" flag for the whole gig only, or you can, for example, set it only for an "extra" option?
What if there's more than one extra?

I just checked and I believe that you can only add it for the entire gig. There doesn't seem to be two shipping check boxes. There is the option to add additional shipping for multiples of an item.