Extension of zonesworld.php?

[Guest]

Hi all,

 

I am using the zonesworld contribution for shipping calculation. My zones are defined as Germany (1), rest of Europe (2) and rest of world (3). So far, this works quite fine.

 

However, I want to be able to give the zone 3 customers the choice between air and surface shipping. Zone 1 and 2 are fine the way they are, so I only need to touch zone 3.

 

Any hints would be greatly appreciated.