Video rendering, Callbacks and ordered sequences

Getting Max to execute objects in a particular order and only advance to the next task once the first task is completed — that is my challenge. The objects in question are those with no call backs.

So here is the context:

I am working a video rendering to movie file project and am continually getting in trouble with Max objects not providing call backs once the assigned the assigned task is completed. For signal and matrix processing no troubles, there is an input and an output once the task is done — there is a definite signal path, so things get executed in the correct order. Now when rendering all those matrices to pictures and saving them to disk, things need to be done in a particular order. So far inserting the delay object is my solution. Ok some examples: mtr object message to begin recording (no call back), jit.record object message to accept images to a file via write message (again no call back). Surely there must be a better way than cross your fingers and if that fails insert a delay on dowstream tasks?

It seems there are a lot of objects in Max that can be called upon to do a task, but you as the programmer can not tell when such a task has been completed. Perhaps I need to think about it a different way.

Thanks in advance, Norman.