Set timeline start date based on completion of dependency item

I’d like to set the timeline of a new item to automatically populate based on the completion date of its dependency item.
The formula would be:
When Item A completes, set timeline for Item B to start immediately and last for days.
I don’t want this to be an automation across the board; rather an item-specific rule per item.
(If Item A is pushed out, then Item B can’t start; this will impact Item C, etc. Each of the Items would need a unique rule.)
How can I do this?

hi @lisak

Welcome to the community. By default all automations run across the board (it would be a lot of automations if you want to do it per item). It can be done with custom development (develop your own app) and create a (set of) rules for which items you want to automate.