Is it possible to create an open box option for my shop to avoid customers paying extra shipping?

[OfLostThings]

Hi, 

is it possible to create an open box option on shopify? I have several customers who like to add bits to their basket during the week or month as new stock becomes available but don’t want to pay shipping multiple times. An open box would allow them to pay for their items as they go and when they chose to close their box they would only pay one lot of shipping costs when the items were sent out. Is this possible? And if so, how?