Even though model-driven engineering reduces complexity during development of self-adaptive systems and models@run.time enables using them during runtime, connecting models to different external system still involves manual work. However, those connections are essential to the complete system, as they enable external systems to react to changes of the internal model and vice versa. In our case, the model is based on Relational Reference Attribute Grammars, an extension of Attribute Grammars to enable conceptual models at runtime while retaining their benefits of modular specification and an incremental evaluation scheme. We present an approach to enable concise specification of the causal connection and needed transformations to match required formats or semantics. To show its applicability, a use-case showing the coordination of multiple industrial robot arms using models is presented. We show, that, using our approach, connections can be specified more concisely while maintaining the same efficiency as hand-written code.