On each image do the following:
Flatten the image if it isn't flattened all ready.
Duplicate the background layer twice cmd/ctrl-J
Rename one layer K
Rename the other duplicate layer CYM
Select the CYM layer and go to the channels and select the black channel and fill it with white
Select the K layer and then go to the channels panel and fill the Cyan, Magenta, and Yellow channels with white.
Change the image mode to grayscale.
Add layer masks to the layers so that you get each layer in the position you want.
Thank you for your assistance. I have followed your steps but get lost when you ask to convert the image to grayscale.
I want to end up with one CMYK Image, that has K only on top, CMY bottom left and K only bottom right.
All in grey to check for grey balance.
I follow your steps, but when I convert to greyscale, of course that's what I end up with, but I would like to maintain a CMYK file, but when checking in say photoshop, top is K, bottom left is CMY and bottom right is K.
Can you help with the last little step. Thank you.
To change it to grayscale, you can go to the top menu and select Image>mode>Grayscale. You can change it back to CYMK afterwards using the same menu. The reason I did this is that at first, I tried just desaturatiing the layers to remove the color, but for some reason there was a red cast remaining.