Dynamically compute document scores...

[William Pierce]

Folks:

During query time, I want to dynamically compute a document score as 
follows:

  a) Take the SOLR score for the document -- call it S.
  b) Lookup the "business logic" score for this document.  Call it L.
  c) Compute a new score T = func(S, L)
  d) Return the documents sorted by T.

I have looked at function queries but in my limited/quick review of it,  I 
could not see a quick way of doing this.

Is this possible?

Thanks,

- Bill