[keycloak-user] Realm Agnostic User Storage SPI

Hi Guys, I am a new keycloak user and have a question. I have a multi-tenant use case and am using different realms/themes to keep users segregated. However I also need an ability to have a separate global default view with all the users/realms without duplicating them across realms for different application. After doing some digging, my thoughts are to have a default realm use custom User Storage SPI to enable additional user lookups that are not part of the default realm. My Questions: 1) Does this sound like I am on the right track or is there a better way of looking at it? 2) Do you know if something similar already exists? 3) Do you see any potential issues with this approach? Thank you, Dmitriy