By using the resource group profiles, you can reduce the number of profiles you need to maintain in the resource classes. Further, provided you avoid defining duplicate member names, using this method reduces the storage requirements for the RACF in-storage profiles that CICS builds during initialization.
RACF provides an in-storage checking service to avoid the I/O operations that would otherwise be needed in RACF. (It does this by means of the RACROUTE REQUEST=FASTAUTH macro.) For this purpose, CICS requests RACF to bring its resource profiles into main storage during CICS initialization.
To make administration easier, avoid defining duplicate profiles. If duplicates are encountered as RACF loads the profiles into storage, it merges the profiles according to the ICHRLX02 selection exit. If no selection exit is installed, RACF follows the default merging rules as indicated in the RLX2P data area. For more information about this, see Resolving Conflicts among Multiple Profiles in the z/OS Security Server RACF Security Administrator's Guide.