I think you need to achieve this by using two data sources.

1. For Group - we have sys_user_group table where you can update the Name of the Group , Manager & Roles.

(You can create a transform map or simply upload the file from the list view using 'Import excel').

Thankyou!

2. For Group members - we have sys_user_grmember table where you can update the Group name & Group Members.