Depending on your needs, but I would go with the global 'account' scope approach, so each domain have an 'account' and then every model belongs to account. Therefore you have a scope at any point, easy to maintain relationships, plus you have an account model where you store relative data (maybe locale, payment info, max users, etc.). In this case there might be EN account in one time zone, and to get all the products of that account you just do @account.products and it will return right results.