Long exposure card destination

In my LUMIX S1R I have a cfexpress card as well as my 64gb SD Card.
I have set the camera up for any video going to the CF as it is faster and much bigger, but I would also like to have my very long exposure shots also going to the faster CF, but I don’t think this is possible to set up. I think before going out on long exposure trips I would have to set all photos going to the CF card..
I think if this is the case then LUMIX has missed a trick not letting you choose different types of shots to go to which card.
Any thoughts?