While information exchange is essential in the policy process, little is known about how divergent subgroups filter actors’ technical and political information exchange, blocking learning processes. Guided by social identity, group entitativity, and self-categorisation theories, we introduce the concept and measurement of identity-based subgroups referring to informal clusters shaped by the self-referent perception of similarities among actors. The identity-based subgroup is recognised as a precursor for coalition building in a policy subsystem but received inadequate attention in the research on Advocacy Coalition Framework. We examine how divergent identity-based subgroups moderate the links between relational embeddedness and technical/political information exchanges in an adversarial fracking policy network in New York. Our quadratic assignment procedure multiple regression indicated that, despite trust, policy actors from different identity-based subgroups are less likely to share technical and political information in the network. When two actors’ identity-based subgroups are different, competition is more likely associated with lower technical information exchange in the network. These findings extend research on information exchange in adversarial policy subsystems.