When you create a System group, the members will be able to have the same privileges, you could share all data with group members, limit group access to specific data, and you will be able to modify group members as needed.
When you convert a User Group into a System Group, you will be able to use this group for group associations, which means that you will be able to assign different attributes to give permission to the group to view and/or manage different information, as well as access specific resources, this way you will have more control over your group (System Group) than before when it was set up as a User Group. The main difference between System Groups and User Groups is that you can apply Security Policies to System Groups.
For further information you can go to the System Configuration Guide from the Signals Notebook Configuration system and choose “System Groups”.