How to allow a non user/1 to approve new user accounts ?

In Drupal 6.9, how can I allow a user, which is not user/1, to approve new user accounts WITHOUT granting him total "administer users" permissions? This is when having the "Visitors can create accounts but administrator approval is required." option selected ?

I find that when allowing/setting the permission of "administer users" in permissions to a user which is not user/1 then he/she can do a lot of things not allowed by user/1 for instance upgrading his role among other things; so I would like to set a non user/1 to approve new users without all the other options that are enabled when setting permissions to "administer users".