I am starting a Juice business and I want to allow customers to purchases packages of 6, 12 and 18 bottles per pack. I want the customer to be able to "build their own box" and choose their flavors. For example a 6 pack is $30 but with the choice of 2 flavors. I can't seem to figure out how to do this or find an app that can help me. Any suggestions would be greatly appreciated.