How do I specify ":layout => false" in Rails' respond_with?

I have this setup:

class UsersController < InheritedResources::Base
  respond_to :html, :js, :xml, :json

  def index
    @users = User.all
    respond_with(@users)
  end
end

Now I am trying to make it so, if params[:format] =~ /(js|json)/, render :layout => false, :text => @users.to_json. How do I do that with respond_with or respond_to and inherited_resources?