Purchasing & shipping multiple products

[melbridgz]

Hi all, 

I am super new to Shopify and trying to set up my shipping profiles.  

If a customer orders 1 x Product A, I have set up the shipping profiles/costs appropriately for delivery either locally or interstate based on weight and size of the carton.  However, if a customer orders 3 x Product A (or in fact multiples of any product) I will either have to send 3 separate packages (and therefore charge 3 x shipping fees) OR package all 3 products into a custom sized package which will obviously incur a higher cost (being that it's a larger/heavier package). 

I can't see any way to customise either of these options in the Shopify shipping settings?

Many thanks in advance!