If the OPSx Subsystem is defined as dynamic, in general the chain of the Subsystems in memory honors the IEFSSNxx definitions first and then the other dynamic entries are started. Just to be sure about that, we provide a sample clist SCANSSCT in CCLXSAMP that can be used to check this chain order. Also using SYSVIEW (if present) You can check the same chain going in SUBSYS option under MVS -> SYSDEFS .
2)Setting SSIMSG to YES
In this case, for all the suppressed messages that Netview needs to intercept, the related MSG rule should check that the MSG.AUTOFLAG value is not set to 0.
.... "MSG.AUTOFLAG The NetView automation flag, which is taken from the WQESAUT bit flag. In addition, the WQEAUTO bit flag is also used. Data Type Integer, read/write Example 1, if automation is specified. Modifying the MSG.AUTOFLAG variable is equivalent to dynamically modifying the AUTO(YES|NO) parameter in the appropriate MPFLSTxx member of the Logical Parmlib Concatenation. For more information, see the IBM documentation. Modifying this variable determines whether NetView processes the message. Using a rule, you can change the value of the variable to 0 (equivalent to AUTO(NO)) or non-zero (equivalent to AUTO(YES))." ....
The above is an excerpt of the information from the link below: