MediaWiki User Rights how to separate rights?

Question

MediaWiki

Good afternoon,
such a question on MediaWiki.
There are 3 groups. Bureaucrat, Admin_1, Admin_2.
1. Bureaucrat. He owns the "userrights". With this right, you can give an administrator or a bureaucrat.
2. Admin_1. It is necessary that he could transfer registered users to the "Admin_2" group. How can I do this without giving it "userrights". Ie that he could not give anyone a bureaucrat or deprive a bureaucrat
3. Admin_2. have the right to edit the texts of protected pages. They cannot change groups, user rights, and so on.

Answer 1

www.mediawiki.org/wiki/Manual:$wgAddGroups
www.mediawiki.org/wiki/Manual:$wgRemoveGroups
$wgAddGroups['Админ_1'] = array( 'Админ_2' );