Linking events is missing a BY clause besides BEFORE and AFTER

[Robert-M-Muench]

I have a high-level ten weeks task. I want to add a review event every week.

week 10: high-level task
by 1 week - 1 day: review
1 week - 1 day: review
1 week - 1 day: review

This should give this:

Today you need a dummy entry that you can reference because it's not possible to specify the start as an offset from the beginning. One can only move it before or after an event.