Pairwise Pseudonymous Identifier(PPID) in KeyCloak

Hello,

I’m currently trying to implement PPID in KeyCloak. The build-in Pairwise Subject Mapper doesn’t offer me the functionalities I want. So I have decided to try and create my own. What I’m looking for is a table linking userIDs and ClientIDs looking like this:

I have created the table in my KeyCloak schema, but I can’t figure out how to access it. Any ideas on how to do this, or maybe a better way to implement PPID?