Much work has been carried out on the topic of BIM-GIS integration. As a technical challenge in particular, research and development tackle the standard data formats of the two areas and aim for the conversion between, linking of or overarching querying over data sources of these formats. Usually, these operational cases (conversion, linking, querying) are examined in isolation or even treated as mutually exclusive and competing approaches. With Triple Graph Grammars, we propose to apply a method that allows to derive solutions for these operational cases from a common generic ruleset. We demonstrate this approach in a proof-of-concept implementation using eMoflon. Our work focusses on IFC and CityGML and we present and discuss a first end-to-end demonstration of integrating these standards with the proposed method. Going forward such representation of the correlation between IFC and CityGML, declarative, independent of particular operational implementations, can serve as a vehicle to capture and document acknowledged integration schemes for IFC and CityGML, complementing these two standards with a specification of their correlation.