Coordination and access control are related issues in open distributed agent systems, being both concerned with governing interaction between agents and resources. In particular, while coordination deals with enabling interaction and making it fruitful, access control is meant to control interaction to make it harmless. We argue that this twofold facet has to be supported by a system in a uniform and decentralised manner. To this end, we describe how the application of the TuCSoN tuple-based coordination model over a hierarchical topology is well-suited in this context. On the one hand, policies can be enforced by means of a single mechanism based on tuples and can be scoped to manage access to groups of distributed resources. On the other hand, agents can interact along a hierarchical infrastructure by applying a standard tuple-based communication template. This makes TuCSoN a single coherent framework for the design and development of Internet-based multiagent systems, which takes coordination as the basis for dealing with network topology and access control in a uniform way.