actually... don't use unless with else. 

and... the way to handle such would be to use [nested_attributes](http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html#method-i-accepts_nested_attributes_for) in combination with [validates_associated](http://api.rubyonrails.org/classes/ActiveRecord/Validations/ClassMethods.html#method-i-validates_associated) at least from the first sight :)