Globalization, climate change, and conflicts generate border security challenges for Norwegian customs (CA). CA governs efforts to mitigate threats related to their mission. Besides operational challenges, some events go beyond standard procedures, affecting multiple interconnected governmental functions like police and health departments. Managing such complexities necessitates a holistic system addressing uncertainties and inter-agency interconnectivity. Resilience-based thinking has shown promise in managing risk proactively. This study applies resilience engineering to explore Norwegian Customs' coordination with other government agencies. We examine inter-agency interoperability in joint operations through Functional Resonance Analysis Method (FRAM). Our findings support FRAM's utility. We recommend strengthening resilience in Norwegian customs facilities through holistic risk management, emergency planning, and cooperation training, and propose further research.