I want to collect the events sent from codepipeline and only propagate the events once the previous stage is done. The codepipeline eventbridge events may be out of order for some reason. Then, once it’s in order, I’d like to send an update to slack posting the information about that stage.

So all of the stages needs to start collecting the events at the same time, in parallel, but they shouldn’t post to slack until the previous step is complete.

This is my current (non working) approach which I hope shows what I’m trying to do:

How can I make this work (if possible)? Note that the problem itself is a PoC, I could solve this in other ways, I’m mostly curious how I’m supposed to handle synchronization within step functions