Thank you so much for your detailed answers and mpp! You are very kind!

I think I understand what you are saying, there are some things which concern me with this implementation, let me know what you think please!

The idea is that at the end, this project will have hundreds of summary tasks like the "hiQCZ". Every one of these summary tasks will have a different duration for phase 1, 2 and 3. What I will try to do is "group" together the summary tasks which have for example the same duration for phase 2 and handle them as one set.

Then basically if I manage to fix the dependencies correctly, when I move the "Pick Up date for phase 2" or whatever you want to call it, then the whole group/set of summary tasks will shift to the left or right depending where I shift the date.

So having that said, I am not sure how to define the appropriate lag duration and if this is beneficial for my approach at the end... I would like not to have lags and go for the ideal scenario. Is there maybe a way to do this without lags?

Thank you!