Under account -> privacy settings -> sharing on Facebook, you'll want to choose "custom" and customize your settings. For each "thing you share" you can further customize who can see it, down to a list of specific people. There are two places to put names, a "whitelist" of people who can see your posts, and a blacklist of people who can't.
One things worth noting here... Facebook has a history of changing how their settings are arranged/applied. Even when this is set, you'll want to keep in mind that there's still a possibility that these people can see everything about you. Such is the nature of Facebook. There is no real security, it's always in your best interests to watch what you post.