A specific permission node to allow a certain group to rank other players up to a specific rank would be nice. What I mean here is for example I want my admin group to be able to do/pex user parent add group Member and /pex user parent remove group Member but not be able to do /pex user parent add group AnotherRank

The bukkit version used to have this so hopefully it will get added soon.

This is an issue for PEX 2.0. The goal is that moderators could change user ranks, but not promote themselves to admins, or promote other users to admins/moderators, or demote other moderators/admins afaik.

"The bukkit version" of what "used to have this"?

As far as I can tell, you're talking about adding inheritances to groups. ("parent" is for inheritance, not "ranking others to a specific rank", which sounds like you're trying to get people to promote/demote others.)

The setting of inheritances is typically the responsibility of the server owner/admin, not users on the server and I can see such an idea leading to the server being ruined easily.

Yeah what zml said. Sorry for not wording it properly. Couldn't find the right terms.

Unfortunately PermissionsEx is currently unmaintained and no further updates are planned. Because of this, all pull requests are being closed. If you are looking for an actively maintained permissions plugin, take a look at LuckPerms. It is compatible with major server platforms and can import data from PEX.