title: How to do not allow a user to create another user with one role in Drupal?
body: <p>I have a user with the role 'manager'. This user can administer other users, so he can create users. In my system I have two other roles, 'representant' and 'client'. The 'representant' can create users too, but my trouble is that he can create 'manager' users. I want to allow 'representant's to create only other 'representant's and 'client's.</p>
  
  <p>How can I do this? There is some Drupal module that treats this problem?</p>
  
  <p>Thank you.</p>