I would like to request the ability to switch a user from a group in one rank ladder, to a group in another rank ladder with the same rank.

For example; if I have two rank ladders LadderA and LadderB, and each has 4 groups with these ranks:

LadderA

10 - GroupA1
20 - GroupA2
30 - GroupA3
40 - GroupA4

LadderB

10 - GroupB1
20 - GroupB2
30 - GroupB3
40 - GroupB4

Now let's say that I have a user User5 who is in the group GroupA3. This means that the user is in a group with a rank of 30. I can promote and demote User5, however only within LadderA. I would like the ability to switch this user into a group in another ladder with the same rank; in this case, group GroupB3 in LadderB, with a rank of 30.
I might use a command like this:
/pex user User5 rank-ladder LadderB
Where /pex user User5 means that the command affects User5, not the group they are in.
Where rank-ladder shows that we are switching the user to another rank ladder.
Where LadderB is simply the name of the ladder the user is being switched to.

If the user is not currently part of a rank ladder, or any specified rank ladder does not exist, or the specified rank ladder does not have a group within it with a rank which matches the rank that the user currently has, then the command simply returns an error message.

This command would greatly simplify many things for me, if possible. Thank you for taking the time to read it.

The command already exists.

/pex user <user> group set <group> [world]
/pex user User5 group set GroupB3

The idea was more, if you want to automate it. Let's say a user has a certain rank on your server, but there are different types of the same rank, and you want them to be able to use a command block to switch to a different type, without changing their rank. If you have a command block that sets someone to GroupB3, and they were in GroupA4, then they lose permissions that they had before.

You'd need a different plugin for that. PEX doesn't handle any automation.