USPS shipping two items

I am looking for a shipping solution and hoping to use USPS - I have not purchased it yet.

As of now, I use Item Shipping which charges customers $5 for each item. If they buy two items, the shipping charge is once for each item ($5 x 2).

Can the USPS combine the package into one shipping cost that is less than the two individual items shipped separately?

Does this use weight, size, both?

Thanks,
Mark

I'm also wondering the same thing...

This is being resolved here:
joomdonation.com/forum/add-ons-payment-s...two-items.html#69606