Automate Connecting Boards with Subitems

I am looking to automate a function so that when a subitem status is changed, a new item is created on a different board and that item is automatically connected to the subitem.

Connecting boards & setting up mirror columns for a subitem manually is allowed, however, when I try to set up the automation the subitem connect boards column is not an option.

Unfortunately manually creating & connecting these items is not functional with our workflow. This automation would be a great help to our project processes.

I think I’ve done similarly to what you’re asking.
What I did was use one the standardized (not custom) automation recipes. And when you create the new column, remember to select “2-way” connection. Once that is done, on the board that holds the items (not subitems) and you should be able to see the connection to the subitem board.
Does that make sense?