External members can't see a mirrored status column from a board they don't have access to

Hi.

I need to mirror one status column of an existing board (Board A) in a new board (Board B) and then allow external guests to view Board B.

I’ve connected board A and Board B and mirrored the column in question and invited the external guests to view Board B. However, external guests don’t see the status column that’s mirrored from Board A (they do see board B and all other columns within it).

They do not (and will not) have permission to view Board A - how do I enable them to see the status column in Board B?

Thanks!