Getting Index When Using render :partial

I’m using a web service to retrieve an array of results to a search
and a render :partial to display those results to the user, while at
the same time putting the results into the session. Is there a way
for my _book.rhtml file to have access to the index of the result
currently being displayed, like each_with_index makes available to
its block? This would allow me to have the client pass back the index
and pull the data from the session, thus assuring that the client
hasn’t fooled with it.

Thanks for any ideas!