Many organizations within both the public sector and private sector will both see benefits and requirements in utilizing EUDI ecosystems. This includes both as issuers and relying party. Many of them operate large system landscapes that include older systems that might be hard to extend with modern prototols. They might also have a system landscape design that does not 1:1 fit the data model schemes of EUDI both in business flows and data ownership. We will describe a concept and patterns to ease implementation for large organizations that have a somewhat complex existing system landscape.