[sametmax]

That's not going to work. Trust and desire to help cannot being batch processed. Well... It can but you need strong leader qualities that few people have.

But you can mix both approaches;

You can do one-on-one to create / maintain the relationship, and utilize social networks to organize the community.

But if you want your local baker to go out of his way to get your child out of trouble, you need to look him in the eyes when you ask for it. And you need to do that for each person you recruit. There is no way around it.