The requirement is for a custom osCommerce shipping module.
I have got several product groups in my shop, for example:
products with free shipping
products with shipping at $10
products with shipping at $20
products with shipping at $40
These are effectively flat rates for each group so for example if one or more products with shipping at $20 is added to the cart the total shipping is still $20
However, if products from different groups are added to the cart the total shipping cost is taken as the highest group shipping cost. For example, a shopping cart with 5 items shipping at $10 and 1 item shipping at $40 the total shipping cost would be $40.
Optional extra to quote on: in the above example, making the total cost the sum or shipping costs from each group, ie in this case $50
I would need also to be able to specify a single product with different shipping costs through attributes eg. small size is free, middle size is $10 shipping, large is $20.
Working for osCommerce MS2.2, PHP 4/5, mysql 5
Any more information required?