Patterns of systems integration strive to accommodate the diversity of business ecosystems, including novel Web- and cloud-based services. In this paper, we apply the principles of the language/action paradigm (LAP) to develop a decentralized integration pattern that supports dynamic integration of services. A model is proposed for designing the interacting systems as active and independent entities that seek to communicate with each other. Two modes are enabled in the communication model: an indirect mode, where systems interact via business processes; and a direct mode, where systems directly interface with each other, following four categories. The communication perspective of the proposed integration pattern contributes to realizing the vision of a marketplace for cloud services. It supports a more flexible alternative to centralized integra-tion patterns. The communication model builds on the improved alignment be-tween system design models and the overall organizational design offered by the unifying meta-model for enterprise modeling.