a-z.rb

def index
  
  @az_idols = ("a"..."z").reduce({}) do |result, letter|
    res = Idol.find :all, :conditions=>["name LIKE ?", "#{letter}%"]
    result[letter] = res unless res.empty?
    result
  end.sort
end

index.html.erb

<% @az_idols.each do |letter, idols| %>
 <h2>AV idol start with <%= letter %></h2>

 <!-- Here will be your old for loop.. just rename @idols to idols and everything will work again -->
 <% for idol in idols  %>
   <%= idol.name %>
   <%= link_to :edit, idol_edit_path(idol) %>
   ...
 <% end %>


<% end %>