A method and apparatus is provided for hosting within a search engine, large-scale heterogeneous repositories of searchable and navigable content. Customers of the hosting platform are customers wanting to outsource the management of their searchable content. Content domain experts from each customer independently define a taxonomy of categories and attributes for their structured content that form a hierarchical set of nodes (a directed graph) that are mapped to a common physical search engine infrastructure. The mapping algorithm that maps unique attributes across potentially very different subject domains onto the same physical infrastructure is introduced. Once the physical structure is created, the search engine can use it for searching or navigating just within one customer's domain or users can search across multiple customer domains. When a customer makes changes to the logical structure, each individual change is categorized as compatible and incompatible, and executed in different time frames based on the amount of disruption it will require to the operational system.