Driven by the question how to identify potential communication partners and the need for well-suited communication schemes in agent-based systems, we discuss two communication concepts: sessions and global event management. Sessions establish either actively or passively a context for inter-agent interactions. Communication partners are addressed by globally unique agent identifiers or via badges. Communication in sessions is based on RPC or message mechanisms. Global event management addresses the need for anonymous communication. Event managers are employed as a synchronization means within agent groups. Based on this approach, we introduce synchronization objects, - active components that offer various synchronization services. The presented model is finally mapped onto OMG event services.