How do I restrict access to learner data by group?

Do you need to delegate or restrict access to learner data by group? In other words, can a specific person only see learner data/reporting who are in the groups that he/she has been access to?

Here's where Restricted Group Administrator role enters the picture. 

1. Suppose we have a group called Group 1
2. Find out who in Group 1 needs to be the restricted group administrator, and select that person's account (or create a new one if it does not already exist). That account must:
   a. be active
   b. be in Group 1
   c. have Administrative Access = Group
   d. have Restricted Group Admin flag set to true
   
   
3. Edit Group 1 such that the learner in previous step is an "Assigned Group Administrators"
   
   
4. When the restricted group administrator logins in, they will only see learners and reports that include learners in the groups for which they have been designated as the Assigned Group Administrators