One way to solve this, assuming that the user doesn't need to wait for it all to finish, would be to add the processing of the entity to the task queue. This would make the microflow kick off in the order in which the tasks are added to the queue.
Another way would be to turn on “disallow concurrent execution” but whether or not this works for your use case is something you'll have to consider.
Hi,
How did you solve your issue? I have same problem.