Full text search with complicated conditions

Hi all,

I am going to do full text search, but only on records that match
quite complicated conditions. I have implemented these as custom
named_scopes, with some SQL. Does anyone know if I can use these named
scopes in filtering out results returned for example by Sphinx? I have
looked at ThinkingSphinx, but it allows you to specify only simple
conditions conditions and does know nothing about ActiveRecord
associations. Is there any other tool more aware of AR than Sphinx?