The publish/subscribe (pub/sub) communications paradigm is suitable for building large-scale, widely distributed applications. Distributed pub/sub middleware scales well because it decouples communicating clients. However, complete decoupling of clients make it more challenging to design distributed applications using pub/sub middleware: often clients want some information about each other. We thus augment the pub/sub communication model through addition of an integrated aggregation mechanism---ASIA---that facilitates bidirectional exchange of information without compromising scalability. Our prototype implementation demonstrates that ASIA can be integrated into a typical distributed pub/sub middleware with little effort, and that the aggregation capability adds little overhead in terms of message throughput and latency.