Getting distinct results per element of an index result

Help
4

As a further simplification, I think the last query can be even reduced to:

q.Paginate(
  q.Join(
    q.Match(q.Index("offers_by_country"), q.Casefold("croatia")),
    q.Index("offers_all_values_by_ref")
  )
)

But I’m still stuck with getting a single offer per uid
I also tried to approach with the tools @databrecht has given in this answer . But no luck, at least for me