Synchronizing Process instances on a file pointer


in our project we have to design a flat file creation process. That means for me, that we have to synchronized the write access to the result file by the process instances.
webMethods provide the services pub.sync.wait and pub.sync.notify for synchronizing issues.
My question is - can I use both services for synchronizing the process instances? My idea is to set the time value for the service pub.sync.wait to value X and the exclusive parameter to ‘yes’. If ten process instances are waiting for a notification (pub.sync.notify) I have to call the service pub.sync.notify ten times and the waiting process instances will write in to the file one instance after another.
Can anybody tell me if this approach is correct or wrong? Has anybody experience with these issues?

Best regards