You can leave the data sets for the intermediate groups in your project unallocated until the first time they are needed for a promote. You can also leave the data sets for types that will not be used at a particular group unallocated. As an example, if a developer is responsible for source code but not panels, then you can leave the data set for the type containing panels unallocated for that developer's group.

A data set need not be allocated if an EXTEND type is being used and the hierarchy is designed so that the source code for the EXTEND type is always at a higher group.

CMNSRC    FLMTYPE
BLDSRC    FLMTYPE  EXTEND=CMNSRC

In this situation, the type CMNSRC can contain members referenced by members in the BLDSRC type. However, if the source code in CMNSRC will always be at a higher layer in the hierarchy (for example, IVV), you do not need to allocate data sets for type CMNSRC below the IVV layer in the main hierarchy.