How to display a mirror column for a low level (2 levels below) board


I have a low-level board B1 in which I have my status.
Than I have a high-level board B2 in which I can display a concatenation of the status of my low-level board B1.
Now I have another high-level board B3 and use B2 as the low-level board of B3. I would like to concatenate the B2 status (which are a concatenation from B1) in B3.

Is that possible ?