Restrict individual posts visibility to certian ‘groups’ or individuals

Heya all! Just a hopefully easy fix that someone might be able to give a hand with!

I’m looking at starting a blog *gasp!*, and want to restrict the visibility of some posts to certian people or groups of people, some to be public, and even hopefully some to be completely private. Is there any easy way to do this? I don’t mind installing a few plugins if that’s the case.

Cheers!

TC