1. A method, comprising: accepting indications of communication conducted among entities over a communication network; using a link processor, analyzing the indications so as to identify that two or more of the entities are interrelated by detecting one or more intermediate entities with which the two or more entities communicate; evaluating a criterion with respect to the indications associated with a given entity; and responsively to meeting the criterion, disqualifying the given entity from serving as an intermediate entity in analyzing the indications.