Its a bit more complex than that unfortunately. Since Rails isn't used to include something like a tenant_id, and doesn't support composite primary keys either

Its a bit more complex than that unfortunately. Since Rails isn't used to include something like a tenant_id, and doesn't support composite primary keys either, you'd have to always hand-write your SQL. Feel free to take a look at the source - it effectively ends up being a default scope with some additional glue code.