Two Prefixes

I don't know for PEX, but I know that LuckPerms can do that
Switch to LuckPerms: https://github.com/lucko/LuckPerms/wiki/Migration#the-process
Set your Prefixes: https://github.com/lucko/LuckPerms/wiki/Prefixes,-Suffixes-&-Meta
And stack them: https://github.com/lucko/LuckPerms/wiki/Prefix-&-Suffix-Stacking
If you need help with it, join LuckPerms' discord server

 

Pex also allows that yeah, not sure about several prefixes though

 

Use a tags plugin, like DeluxeTags.

 

Then, that way you can set it up to have the tag behind the prefix.

 

Hopefully that was a suitable answer.