Multiple shipping packages; Computing weight of a single package

I just want to verify whether nop 1.4 can currently support either of these:

1. Only 5 items can fit in a package.  Therefore, if someone orders > 5 items we need nop to "create" multiple packages.

2. Compute weight of 1 package based on this formula:

    total package weight = "empty package weight" + ("item weight" * "number of items in package")

not an option i'm afraid - can you utilise 'Additional shipping charge:'  on product varient to try cover the cost of + items (not a great solution i know)?

Thanks for your reply.

No, actually we need to interface with the USPS API.  So my plan is to write a custom USPSComputationMethod based on the cart, not on a package.