To assign System Alias proceed as follows:
In transaction SPRO open the SAP Reference IMG and navigate to: and click on the Activity icon.
Select the GSDO Group created in the Creating GSDO Groups section.
Choose and double-click Assign GSDOs, the added GSDO will be present in the list.
Select the GSDO Group, and click Assign SAP System Alias:
User Role: A specific User Role can be maintained which will be checked to link to the designated system.
SAP System Alias: Add entries for system aliases to be added.
Select the System Alias and click Assign User Roles: User Roles can be defined here.
Blank: Refers to All Roles.