Basically, I have the same question as [this one](https://stackoverflow.com/questions/6334231/rails-3-radiobutton-group-in-fields-for), which unfortunately never got a satisfying answer. 

I have a User model, and each user can have multiple associated addresses in the Address model (one-to-many relationship). Now, what I would like to accomplish is that from the associated addresses of a particular user, I can designate one address as the billing address. For this I have a boolean column in the address database table called billing\_address. I would like to set the billing address in the user form with the help of a radio button, but I get either a situation that I am able to select all addresses, like this:

```
<%= form_for @user do |f| %>
  <%= f.fields_for :addresses do |a| %>
    <%= a.radio_button :billing_address, 1 %><%= a.label :billing_address %>
  <% end %>
<% end %>

```

or that I am not able to send the billing\_address parameter to the controller correctly, like this:

```
<%= form_for @user do |f| %>
  <%= f.fields_for :addresses do |a| %>
    <%= radio_button_tag "user[addresses_attributes][billing_address]", 1 %>
  <% end %>
<% end %>

```

Any help help is appreciated to get me the right syntax. Or maybe this is not the correct approach to what I try to accomplish at all?