How to give moderators less or more rights

[Zapmi]

Hi guys,

I have my own server, and i am in need of another moderator!
I am using my friend as a "test" now to see what a moderator can do on the server, and quite frankly, it's too much. Spawning items and flying is my biggest concern!
Can't trust random people, even if i've gotten to know them a little with that kind of power on the server. It's too easy to abuse..

Is there a way to edit the rights the moderator have? Create a new group and assigning permissions? How do i find those permissions?

Hoping for a great solution by you guys,

-Zapmi