Abolishing the employment contract isn’t more constraints than ancap. It is part of legitimate contracts’ non-fraudulent nature.

I meant in general - two sides in ancap may voluntarily decide whatever concerns them both via any mechanism they come up with, but if that violates the rights of others, the others of course are not obligated by it in any way, or if it transfers responsibility in this case, others are not obligated to follow that transfer.

Here we have something less relative and more static.

Groups could have judicial systems. Judicial agreements could exist between groups. Thieves would pay damages to the victim. For serious crimes, there could be expulsion from group(s) and blocklists

OK. This is as bad or as good an answer as for ancap, because it's the same answer.

In general what you describe is technically a subset of ancap+panarchy, which is what I meant by more constraints.