Actvity msgs showing wrongly in monitor

Hi All,
we have a service which submits multiple documnets to TN.A process model gets triggered for each of the docs submittted.The issue we are facing is if we click on a single instance of process model in monitor,we are seeing activity messages for all the transactions occured during that time frame submitted by that service.we expected to see activity msgs for a single instance separately.
so lets say if we submit 6 docs to TN,6 instances of process model get triggered.If we click on one of instance in monitor,we see activity msgs for all the 6 processses in that page instead of showing msgs for that single instance only.Is it a normal bhaviour.can we avoid this from happening so that we can track each instance effectively??