Depending upon the hood it might be easy enough to make a fixed mask (matching the format) or adjustable blades and fasten it / them (and reposition it for landscape versus portrait format) via velcro dots.

That is the solution I am looking at to use the same hood for my 8x10 and 8x20 cameras.

Figuring out the mounting for the hood itself on two very different cameras is the bigger issue for me.

Hopefully that is a useful concept to you,