I've mentioned a few times that recipes aren't really blueprints to build by. They are guidelines. Like you there are many things I simply can't buy because my local stores don't carry them. Either you substitute, make your own, or don't do.
While both cheeses are readily available here in block, shredded, or even artificial styles. Some cheeses won't work, such as if you get one of the strong, smelly, cheeses. But I would think while you might not have the ones called for, you probably have some very similar locally. You won't come out with the exact same taste but it ought to be close enough to enjoy.
Since I live in a small town there are many food ingredients I simply can not buy. The nearest store that would be likely to carry it would be at least 60 miles away. So often I figure out what will work that either I can make or I can substitute in it's place.