The state always takes precedent, since from its own perspective, contract-like things made in other organizational structures have no reality to it. This leads to some interesting intersections where a subgroup enters into an agreement that has important meaning within the group, and no meaning to the enclosing entity (the state). Think religious practices of non Judeo-Christian religions; or ceremonial agreements of native people, etc. Even things like sports leagues, which have their own rules: should players have been able to sue Bill Laimbeer for playing dirty, or should his bullshit only be adjudicated by the League? When does a foul become assault?

It's possible that the wiki isn't a great intro if you don't know something about it already -- I learned about it from it being mentioned on various podcasts. Jim Rutt talks about it alot, he was one of the "founders" of the movement; another was Jordan Hall, formerly Jordan Greenhall. Both very interesting and smart guys.