Grouping by attributes within a form_for - ruby-on-rails

Question

I am working on a Rails project that requires preferences for diferent user types depending on which shool. Thus i have these models:
class Preference < ActiveRecord::Base
belongs_to :school
belongs_to :privilege
belongs_to :user_type
end
class Privilege < ActiveRecord::Base
has_many :preferences
end
So in my view, i wish to edit the preferences for a given school and i wish to separate and order by user type. So for example my finished view would look like this:
<form accept-charset="UTF-8" action="/preferences/edit" method="post">
<table>
<thead>
<td>Pivilege</td>
<td>Allowed</td>
</thead>
<tbody>
<h2>Student User type</h2>
<tr>
<td>Privilege 1<td>
<td>checkbox for privilege 1<td>
</tr>
<tr>
<td>Privilege 2<td>
<td>checkbox for privilege 2<td>
</tr>
<h2>Employee User type</h2>
<tr>
<td>Privilege 1<td>
<td>checkbox for privilege 1<td>
</tr>
<tr>
<td>Privilege 2<td>
<td>checkbox for privilege 2<td>
</tr>
</tbody>
</table>
</form>
The problem is i do not know how to itarate within a (form_for #preferences do |f|) block and group this array (#preferences) by user_types.
Can anybody help me? Thanxs in advance

Answer 1

I ended up using nested attributes and verifying if the preference belongs to that user type (although I insist that there should be a more "Rails way" of doing it. Hopes this helps somebody:
<%= form_for #school, :url => {:controller => :preferences, :action => :update, :id => #school.id} do |f| %>
<h2>Change Preferences</h2>
<% UserType.all.each do |ut|%>
<h3><%= ut.name%></h3>
<table>
<thead>
<td>Privilege</td>
<td>Allowed</td>
</thead>
<tbody>
<%= f.fields_for :preferences do |pref| %>
<% if pref.object.user_type == ut%>
<tr>
<td><%= pref.object.privilege.name%></td>
<td><%= pref.check_box :allowed, {:allowed => pref.object.allowed} %></td>
</tr>
<% end %>
<% end%>
</tbody>
</table>
<% end %>