save group (and stem?) should set parent display extensions if creating them

{

    "WsRestGroupSaveRequest": {

        "wsGroupToSaves": [

            {

                "wsGroup": {

                    "extension": "undergraduates",

                    "description": "ATMS 120 HB Fall 2021 Undergraduates",

                    "displayExtension": "Undergraduates",

                    "displayName": "Reference:Class Rosters:service:sandbox:2021 Fall:ATMS:120:HB:Undergraduates",

                    "name": "ref:roster:service:sandbox:120218:ATMS:120:120218_52474:undergraduates"

                },

                "createParentStemsIfNotExist": "T",

                "wsGroupLookup": {

                    "groupName": "ref:roster:service:sandbox:120218:ATMS:120:120218_52474:undergraduates"

                }

            }

        ]

    }

}