How to mirror a field of a subitem of Board A to an item of Board B?

I have a Board A with items and subitems
The subitems have a Number column X
The subitems have a linked column that is connected to Board B

On board B I want a mirror column of Column X that SUM the values of cloumn X

However I cannot select a subitem-column of board A on board B when configuring the mirror column on Board B.

So it seems that it is not possible? Or am I wrong? Does anyone knows a trick how to do this anyway?


  • Board A item: Purchase Project

  • Board A subitems: purchase orders (belonging to the Purchase Project) with purchase value field and Supplier column (linked Column to Board B items: link one-only)

  • Board B item: Supplier, mirrorColumn: total-PurchaseValue of board A subitems

Hey @loovanloon,

Does this demonstration help?

To confirm, you will need to set up the connect boards column via the subitems when connecting subitems to parent items in secondary boards. Please reach out if I’ve misunderstood the request :pray: