In anticipation of the change to AllowUserKeyCSA(NO) we will change CVs to run in key(4).
However, all CVs execute the same startup program RHDCOMVS so if we add the PPT entry for RHDCOMVS it will affect all CVs once it is enabled.
How can we test this one CV at a time?
Documentation on bringing IDMS CVs up in the recommended Key(4) is in SYSTEM OPERATIONS section Storage Key Considerations for z/OS CSA Subpools.
It is true that CVs will typically execute the same startup program name RHDCOMVS (or alias IDMSDC which some clients use) so that if you add a z/OS PPT entry for this program name it will affect all CVs.
However, the PPT entry attributes such as KEY will only be honored if the STEPLIB from which the startup program is loaded is APF authorized.
Therefore, to test one CV at a time you can add the PPT entry, then ensure that the STEPLIB in the startup JCL for the CV you want to bring up in the specified KEY has an APF authorized STEPLIB and all other CVs have STEPLIB that is not APF ( adding a non-APF loadlib at the bottom of the STEPLIB concatenation will effectively make the STEPLIB not APF).
This way, when you are ready to test the next CV you simply remove the non-APF loadlib from STEPLIB so it includes only APF-authorized Loadlib(s).