Yes, that is possible.  I sometimes say that my cats "specialize" because I
find that they seem to use their boxes for separate purposes -- but not to
the extent you describe.

MaryL

It's quite possible. I have one cat and two litter boxes and more often than
not, she'll poop in one and pee in the other. I figure when she does both in
the same box it's because she really has to go!! :c)

When we're outside for our walks, it's pretty much the same thing. She
doesn't often do both under the same bush.

Judy

Our 7 indoor-only cats change their litterbox habits on a daily basis.
Some days one box will be full, the next day it will be empty. One day
one box will have only poops, the next day only pee. I have no idea why
they do it, but if it makes them happy, I dont' care... :)