OLAP tools divide concepts based on whether they are used as analysis dimensions, or are the fact subject of analysis, which gives rise to star shape schemas. Operations are always provided to navigate inside such star schemas. However, the navigation among different stars use to be forgotten. This paper studies different kinds of conceptual relationships between stars (i.e. Derivability, Generalization/Specialization, Aggregation/Decomposition, or Temporal), and proposes a 3-level schemas architecture to ease the implementation and usage of multi-star schemas.