Can I put two boxes in one shipment?

[deckdolly]

I have flat rate shipping on my products and was wondering if I can combine two packages into one shipment? Currently when I get an order for two or more items I split the shipment and then I just create separate shipments. Generally space does not allow me to ship in the same box but can I save money by having two boxes in one shipment?

If so, how do I do that?

Thanks,

Kyle