Middle-agents are used by end-agents to locate service providers in multi-agent systems. One central middle-agent represents a single point of failure and communication bottleneck in the system. Thus a structure of middleagents can be used to overcome these issues. We designed and implemented a structure of middle-agents called dynamic hierarchical teams that has userdefined level of fault-tolerance and is moreover fixed scalable. We prove that the structure that has teams of size has edge and vertex connectivity equal to and is maximally fault tolerant. We focus on social knowledge management describing several methods that can be used for social knowledge propagation and related methods to search for knowledge in this structure. We also test the fault-tolerance of this structure in practical experiments.