As enterprise architecture initiatives grow to span multiple teams, geographies, and time zones, the repositories and tools supporting them face real challenges: information overload, ownership conflicts, version management, and the need to present different views to different user communities. This paper formalises a set of meta model and meta-meta model extensions — including context, domains, filters, versioning, and scenarios — developed through real-world deployment of a collaborative EA modelling platform. The result is a more manageable, flexible, and scalable foundation for large-scale collaborative architecture work.