How to un-merge 2 contact/Address books from iCloud

I have 2 accounts on my MAC.
(1)
My primary

(2)
A Christmas (Holiday) one, I use it once a year.

I went into the Xmas one and it had several updates and iCloud was one of them

What has happened is that both address/Contact books merged together.

How can I undo this and keep the 2 Contact books separate?

Thanks

Greg