Need help with setting up shipping this way

I sell three products. Ex. Product a, Product b, product c

For product A, shipping,

Shipping Option Overnight:
1st item = $17.59
2nd item = Add $5

Shippign Option Priority:
1st item = $10.59
2nd item = Add $3

Shipping Option Ground:
1st item = $7.59
2nd item = Add $2

And the same model goes for Product B and Product C.

How can I implement this way of shipping in Zen cart?

What if I order 1 A and 1 B

Overnight Shipping:

$17.59 + $ 9.99

Priority Shipping
$10.59 + $6.78

Ground
$7.59 + $4.59

In other words, it will ADD the shipping value of the base products.

ALso, i must add that product does not mean one of the million products, but product categories or sub groups of products. .

CartCrazy:

I sell three products. Ex. Product a, Product b, product c

For product A, shipping,

Shipping Option Overnight:
1st item = $17.59
2nd item = Add $5

Shippign Option Priority:
1st item = $10.59
2nd item = Add $3

Shipping Option Ground:
1st item = $7.59
2nd item = Add $2

And the same model goes for Product B and Product C.

How can I implement this way of shipping in Zen cart?