What options do we have to put a stop to our neighbor's harassment?

My family and I have been enduring a neighbor dispute for almost 2 years. We recently decided after many kind attempts for resolutions, to file a report with the police department. We share a duplex with these neighbors and they will stop at nothing to cross our personal boundaries. Intrusive noise, music, banging all hours of the day. Their kids peeping in our windows, vandalizing, friends over who help them cause us trouble, damaging our property, scratching up our vehicles with their bicycles, littering on our lawn, slandering us, bullying my children at home and harassing my children at school. They are bullies and don't understand quiet enjoyment. We found out at after moving in from a nearby neighbor that they and their children have a reputation for causing trouble and damaging property. We are not in a position to move. We want to as soon as possible. The police keep telling us to report each incident. We don't have time for this nonsense. We are private, busy, active in our community and want to come home at the end of the day to relax. It is not possible with these people. Our landlord has stated he is afraid of losing tenants and needs rent pay and will not pursue this. He has tried reasoning with them with no success. They are unreasonable, defensive and act like victims when we try to reach a solution with them. They do not want to be responsible for their actions or their children's. What kind of NH lawyer can help us? What options do we have to put a stop to this? We want them to leave us alone and make it clear that we are not going to put up with this. Any suggestions would be greatly appreciated. Thank you.