hanging my tomorrows on the bones of yesterday

The A's have C's in the social network because they like to help but don't like to be helped, or have some aversion to putting themselves out there to get help. So trust isn't really needed, because the C's are fulfilling a function for the A's -- someone to help. Chances are good that the C's need a lot of help. So the A's can enable the C's. It's not a healthy dynamic, but it is functional in its own twisted way. (And this isn't a healthy twisted, either)
Also remember that extroverts tend to collect friends like skanks tend to collect STD's, so they may not feel the need to trust everyone because they have a large social network.
What you're really describing here is the pendulum experiment from an Acoustics lecture that simulates wave propogation. Take two pendula and link them, and then set one in motion. The motion of that one transfers to the other one, and that one stops. Then the energy is transferred back. Link in another, and the energy is transferred down the line and back again in something of a wave. When I saw this in Acoustics class it hit me that there was something deeper in the experiment that dealt with something metaphysical, but it took some time deliberating while I was lying in the hospital losing my sight to figure it out. (Ironic, that, as my inability to ask for help when needed is one of the reasons I lost my sight in the first place) This kind of energy transfer is important for the following reason: GGrab one pendulum, arresting its energy flow, and th entire system stops. This is true even if it's the currently static one, as energy transfer to it will arrest the entire system.