I think the only way to do that would be to use scopes to allow each duplicate friendly_id
to exist in its own "scope space".
https://github.com/norman/friendly_id/blob/master/lib/friendly_id/scoped.rb#L7
I'm guessing something like this (assuming that the duplicate friendly_id
s belong to different users
s):
class Product < ActiveRecord::Base
extend FriendlyId
friendly_id :tite, :use => [:scoped,:slugged], :scope => :user
end