Additional shipping option

HI, need a bit of advise setting up shipping in opencart.
I'm wanting a weight based shipping system based on shipping address, that's all good I can set that up with zones etc.
I also want another check box option that adds an additional weight based shipping cost to any of the zones.

I'm in NZ and we have what is called rural delivery with is an extra cost of $5 /15kg on top of the standard rates for each zone.
is this possible?

cheers
Tim

Did you work this out Tim?

Check out my tutorial on how to create multiple flat rates (or weight based rates) using Weight Based Shipping:

http://forum.opencart.com/viewtopic.php?f=142&t=86202

It basically involves creating a duplicate geo zone, which can then be used for the second shipping option.

Thank you!