Xmanager STC proc - optional parms - GROUP

Products

• Bind Analyzer for DB2 for z/OS
• SQL-Ease for DB2 for z/OS
• SYSVIEW Performance Management Option for DB2 for z/OS
• Plan Analyzer for DB2 for z/OS
• Subsystem Analyzer for DB2 for z/OS
• Database Management for DB2 for z/OS - Performance Suite
• Database Management for DB2 for z/OS - SQL Performance Suite
• Insight Performance Monitor for DB2 UDB for z/OS

Issue/Introduction

One of our other regions use the GROUP option on the Xmanager proc, for example:

OPT='GROUP(DSGP)'   where DSGP is the DB2 Data Sharing Group Attach name.

Apparently this was done in the past during the initial install, but I cannot obtain any more details on why this was done.  

Nor can I find this option documented here:
 
https://techdocs.broadcom.com/us/en/ca-mainframe-software/database-management/ca-database-management-solutions-for-db2-for-z-os/20/installing/complete-product-configuration/execute-product-specific-tailoring/customize-xmanager/prepare-the-xmanager-started-task-procedure.html
 
I would like to understand why this was recommended.
 
I can see that the Xmanager reference this group:

PXM4710 XMANAGER PLEXCNTL GRP=DBA3     MEM=XMAN4000FSS2

Environment

Release : 20.0

Component : Execution Manager

Resolution

Detector, Subsystem Analyzer, and Thread Termination/Dynamic DSNZPARM support remote DB2 subsystems, i.e. DB2 subsystems running on other LPARs, by utilizing Sysplex services support built into Xmanager. In order for Xmanagers running on different LPARs to communicate with each other via Sysplex services, the Xmanagers must be in the same Sysplex services group. The Xmanager GROUP parameter is used to specify the Sysplex services group explicitly and thereby limit which Xmanagers can communicate with each other across LPARs.

There is no need for the name specified via the Xmanager GROUP parameter to match a DB2 data sharing group attach name; the Xmanager GROUP parameter has nothing to do with DB2 data sharing groups.
 
The Xmanager GROUP parameter is optional because when one is not specified, a default Sysplex services group is used. However, in some cases, preventing certain Xmanagers from communicating with each other may be desirable.