Serious Calling Skype Group

Not really sure where to put this, so move it if this would be considered the wrong section.
I've been trying to find out how to make it so that users in my skype group cannot call the group.
It would seem to have been done with the Nulled Skype Group, so I know it is possible.

If anyone knows how to do this, lemme know.
If you have a list of more advanced and harder to find skype commands, I'd very much appreciate it if you'd share them with me :yus:

Thanks in advance.
<3