Subitem inherit column values from Parent

Simple request that I think would be very useful- Would love the ability to grab column values from a sub items parent in the sub item itself, primarily for function column usage.

I’d like to be able to do calculations on values in specific sub items using a value set in the parent item. For example- Using parent items in a group to be POs and sub items of each PO to be billing points/line items. If I could communicate between sub item and parent item, I could fill out price points in columns per PO and then calculate totals based off of each sub item.

PO A bills at $1.00 per foot and has 5 sub items which refer to 5 different footage orders to invoice
PO B Bills at $1.50 per foot and has 3 sub items which refer to 3 different footage orders to invoice

If I could communicate between sub items and the parent item, I could input the price point in the parent item and use a formula to calculate total charges for each sub item based on price point set in the parent. Then I could relay that value summary back to the parent and determine if a PO is running low or not.

We have tried work around such as mirroring columns from the same board, but these don’t allow you to set defaults or anything, so unfortunately its just another column the user has to click. Plus mirroring a column from the same board seems kind of clunky.