The maintenance of data warehouses(DWs) is becoming an increasingly important topic due to the growing use, derivation and integration of digital information. Most previous work has dealt with one centralized data warehouse only. In this paper, we now focus on environments with multiple DWs that are possibly derived from other DWs. In such a large-scale environment, data updates from base sources may arrive in individual data warehouses in different orders, thus resulting in inconsistent data warehouse extents. We propose to address this problem by employing a registry agent responsible for establishing one unique order for the propagation of updates from the base sources to the DWs. With this solution, individual DW managers can still maintain their respective extents autonomously and independently from each other, thus allowing them to apply any existing incremental maintenance algorithm from the literature. We demonstrate that this registry-based coordination approach (RyCo) indeed achieves consistency across all DWs.