Dependency on multiple items

Hi,
I’m trying to set up a project schedule to make automatic date adjustments to dependent items based on changes to precedent items.
Where an items has a single precedent item, using the dependency feature works well.
However, in most cases for me a dependent item’s timeline depends on multiple precedent items. i.e. I need the dependent item’s timeline to change in response to a change in the SUMMARY of the timeline of all the precedent items. The dependency for every item may be unique (i.e. some items may depend on 2 precedent items, others may depend on 8 precedent items).
My workaround for this has been to create a separate board replicating the dependent items, linking the replicas together and mirroring the timeline from the original board to the replica, then linking all the precedent activities from the original to each dependent’s replica on the other board (this makes the mirrored timeline column in the replica board summarise all the precedent items’ timelines). I then mirror the summarised timeline column from the replica board back to the original board so I can compare the “actual” timeline of the dependent item with the summarised timeline from the replica. Then I have to manually update the “actual” timeline to match the summarised timeline.
This is far from ideal because it’s very time consuming and confusing to manage, especially when an item is often dependent on various other items and also a precedent for multiple other items.
Is there a better way?