Different Shipping Based on Product Quantity

Thank you very much for Eshop, it’s been great using it and is very handy in a lot ways.

I am having some difficulties though and was wondering if I could have guidance for setting up the shipping so that based on various combinations of products different shipping rates will be assigned when the customer is doing the check out.

The company the website is for is a small independent publisher in a specialized field and they currently have two publications available (with a third being launched in a few months). The company using a book distributor that handles the packing and shipping of the books to the customers; they use a flat-rate shipping fee. Where the difficulty comes is that the distributor will use different size boxes depending on how many books there are in the order. Here is layout needed are for the various scenarios:

Geo zone 1: USA
Shipping: medium flat-rate: $X1, large flat-rate: $X2

Geo zone 2: All countries except USA
Shipping: medium flat-rate: $X3, large flat-rate: $X4

[Just assuming the customer is local for now]
If total quantity of products = 1 or 2 then shipping = medium flat-rate
If total quantity of products = 3 to 6 then shipping = large flat-rate
If total quantity of products > 6 then message displays asking customer to contact the company directly

How would it be possible to set this up with Eshop? Or could this only be done by the shipping plugin and if so how can this be done?

Also, while the company’s first two publications are the same size, their third planned publication is a different size which could make the shipping more complicated. What would be ideal would be able to input different combinations of products and then assigned a set shipping amount to that combination, for example:

Items A, B: medium flat-rate
Items C: medium flat-rate
Items A, C: large flat-rate
Items A, B, C: large flat-rate
Items A, B, 2 x C: large flat-rate + medium flat-rate
And so forth

Would something like this be possible?

Anyway, thank for you attention.

UPDATE:

So it turns out that the solution was there, I didn't look closely enough at the Quantity Shipping plugin. In case this would be helpful to anyone else, I achieved what I was aiming to happen in my original post by using the quantity shipping plugin in to have one amount for 1 - 2 products, another amount for 3 - 6 products, and then set the max quantity for both the two publication to 3, and changed the error message for when a customer orders more than the max quantity in the translations part to asking the customer to use a contact form (hyperlinked to another part of the site).

As for having different local and international shipping rate, I came across a Quantity Shipping plugin in another thread, so now I can use one plugin for the local rates, and the other plugin for international rates. It is going to take a while though to create a Geo Zone with all the countries except the US but seems like it should all work.