moto_man is correct in that you need to go after everyone. During the time I worked in insurance, all claims made by condominium owners for things that went wrong on a major scale sued everyone involved with the construction, no matter how small the job was.
It was like a wake up call that the owners weren't messing around and forced all parties to get together in a timely fashion, eliminate those who couldn't have been involved, and bring it to an end in a timely manner.
Once they have to respond in court, they start to behave.
All the best,
Nonoise