Combine Table Rate and First Item $X, Additional I

[Guest]

I need to combine Table Rate and First Item $X, Additional Items $Y Shipping.

How do I do this?

 

So this is how it works:

 

Shipping Rates are as follows:

0-$25.00 ship cost 9.00

25.01-50.00 ship cost 11.00

50.01+ ship cost 13.00

Each additonal item is 5.00 extra

 

So example

 

Item A is 55.00

Item B is 17.00

 

Item A + Item B = $18.00 for shipping

[Guest]

Any help