You might want to look into distributed transactions to see if they can be applied to your problem.
http://blog.notdot.net/2009/9/Distributed-Transactions-on-App-Engine -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
