A plethora of context infrastructures have been developed to support the deployment of context-aware systems. Unfortunately, it is not easy to re-use the design principles adopted in a certain context infrastructure in order to leverage some characteristics of another one, as such principles are often hidden into the infrastructure and not independently explicated. The aim of this work is to propose a methodology to develop a pattern language for context-infrastructures and promote the re-usability of proved techniques to support context-awareness. We describe the proposed methodology with respect to a specific requirement, that is to ensure the interoperability among context-sensitive entities. We specifically define a design pattern to reach this goal, namely the Context Matcher pattern, and we show how to apply such pattern to an existing infrastructure in order to leverage its interoperability.