A method and system enable robust and scalable propagation of trust between a first organization and a second organization, both operating in an ad hoc wireless communication network. The method includes establishing at a first member node of the first organization pair-wise trust with a first member node of the second organization using a predetermined inter-organizational trust establishment device (step 505). Next, the first member node of the first organization generates a credential for the second organization using the pair-wise trust (step 510). The credential is then distributed from the first member node of the first organization to a second member node of the first organization (step 515). The second member node of the first organization then establishes pair-wise trust with a second member node of the second organization using the credential received from the first member node of the first organization (step 520).