Setting up expunge rules on a per user basis?

Hi all,

I was wondering, is it possible to setup for instance expunge rules on a per user basis, when I am using userdb SQL lookups (or, possibly via post-login scripts)

Reading the docs it seems like its possible, but I am not entirely sure about the data I should return, so have any of you done something like this, and could maybe post an example?

-- Peter Reinhold