As in openfire obtain the effect that the new user, after logging
through instant messaging PSI saw two groups: help, admin and users in
those groups (help: help1, help2, help3, admin: admin1, admin2).
Is it possible to achieve this in openfire?
You should take a look on shared groups.
Create a group “admin” and:
enable contact list group sharing
share group with additional users, either all users or some specific other groups
Same for group “help”.
In this context the Helga-Bot could be useful for you. It does allow users to join and leave groups, so they can choose if they want to see all that admins in their contact list simply joining or leaving a group “SeeAdmins”.