Hello 'bhal7789',
Is there any mention in the seller's listing about an offer of combined shipping? Most will say so if they offer it. Some have the listings set up automatically so you can choose the quantity you want of each, and the discount is tallied automatically when you pay at the checkout. Is there an option to change the quantity from 1 to 2 or more?
If you cannot order multiples and there is no mention of a discount then you will need to contact the seller in advance of buying to explain what you would like and how many. It's also a good idea to ask specifically "what do you charge..." because many sellers will assure you they offer a combined rate, but after you buy you discover the savings is miniscule and not worth it at all.