ActionMailer method level layouts

I am using layouts in 2.3's ActionMalier.

I know I can specify a layout at the class level:

class MyMailer < ActionMailer::Base
  layout 'foo'
...
end

Is it possible to define one at the method level?

i.e.

class MyMailer < ActionMailer::Base
  layout 'foo'
...
  def invite
   # USE LAYOUT FOO2
  end
end

thanks.

render :layout => 'foo'

Are you sure?
ActionMailer is a model.
Render is for view.

Render is a private method on ActionMailer.

http://apidock.com/rails/ActionMailer/Base/render

Any one else have ideas on how I can achieve this? Is it possible?
(looking at the core source - nothing obvious comes to mind).