How can I make rectangles behind subgraphs equal size?

[avatar-lavventura]

Here the rectangles behind subgraphs are not the same size.

code:

flowchart TB
   subgraph w1
       A
       B
       C
   end
   subgraph w2
       D
       E
   end
   subgraph w3
       F
   end
   A & B & C --> D & E
   D & E --> F

As you can see second subgraph's rectangle is smaller than the first one, and third subgraph's rectangle is smaller than the second one.

Is it possible to make rectangles behind the subgraphs equal size to make it look symmetric?