Order of error_messages_for

Is there a mean to specify the messages order that are displayed by a

I see that we can specify the objects order. But what about the
messages related to a same object.

Let say I have an Order.

In my form I have the following order:
Payment type

and in my model I have:
  validates_presence_of :name, :address, :email, :pay_type
  validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+

However I get the following order for the error messages:
    * Name can't be blank
    * Pay type can't be blank
    * Address can't be blank
    * Email is invalid
    * Email can't be blank

Obviously I would like the same order as in the form.

Is it possible with error_messages_for ?

You could use:

<%= error_message_on :order, :name %>
<%= error_message_on :order, :address %>
<%= error_message_on :order, :email %>

Hope this helps.