In the Composition and Collaboration perspectives, you can select from the following hierarchies:

1. File Hierarchy. This organizes the model according to the file-system structure (directories and files). Drilling down into files will reveal the logical Ada structure.
2. Logical (unmerged) Hierarchy. This shows the logical Ada package hierarchy. E.g. package A.B is shown inside package A. Package specifications and package bodies are kept separate. When an item in one package uses an item in another package, the dependency will be on the used item's specification. (You can additionally show the "implicit" dependencies on the used item's body from the project wizard or properties).
3. Logical (merged) Hierarchy. Package specifications and bodies are merged into a single "package" item. Each item has only a single incarnation (rather than a spec and a body). Important: you should enable "implicit dependencies" in the project wizard or properties in order to create a complete model.
4. Logical (augmented) Hierarchy. Similar to the "logical merged" hierarchy, except that any code items other than subpackages are grouped together as "(locals)" under the parent package. This hierarchy is used by the Slice perspective.