I have 3 groups: default, Premium, Ultra. They are connected to parent groups. How can I do that for example in default-perms: teamspeak.default, premium-perms: teamspeak.premium and ultra-perms: teamspeak.ultra. That is all permissions for only 1 group.

But if I have Ultra Rank, he'll take rank.default, rank.premium, and rank.ultra.

How can I do the rank.premium only for Premium and not for Premium and Ultra?

Simply set permissions to false if they are inherited.

E.g: in the premium group, set teamspeak.default to false and in the ultra group, set teamspeak.premium to false.

Thank you :D