How can I apply two different shipping classes to one product?

Hi

I am struggling to find a solution to my problem of requiring different Shipping Classes for different Shipping Zones for the same product.

Here’s my situation:
The Product: Silk Ties.
The cost of standard “national” delivery is $9.95.
The cost of the standard “international” delivery is $15.

I have set up two Shipping Zones: National and International.

When editing the product, I’m only allowed one option of Shipping Class.

How can I apply the two different Shipping Classes (standard national and standard international delivery) to the one product?

Thanks,
N.