If you do not use only cholov Yisrael, try swallowing a pill with some Ensure. The just-right thickness of the drink, helps the pill to go down more easily. I can swallow at least 6 vitamins at a time, of assorted sizes and shapes.
Alternatively, perhaps there are chewable or liquid versions of those vitamins. Whatever you do, do not take them apart or crush them, if they are meant to be swallowed whole, as they might need to be in the stomach for a certain amount of time before being absorbed.