CanCan filtering meta_search results?

At the moment, I am running meta_search, and then filtering through CanCan after I have a set of results. Is there any other way to restrict the returned objects within the initial search query?

   def index      @search = User.search :first_name_or_last_name_or_practice_name_or_role_contains_any => params[:search].to_s.split(' ')      @users = @search.order('last_name ASC, first_name ASC').accessible_by(current_ability).page(params[:page])    end

Thanks in advance,

Walter