Would it be ok to keep two adult cats in a dog crate for a few hours a day?

Hmm.. I'm not really sure. I put two of my cats in a large cage just to go to vet, and they were hissing at each other and started fighting. These cats are INSEPERABLE, they were from the same litter, we adopted them together, and never fight but, when they were in the cage together, they reacted really different, so I'd be careful. Maybe you could give them seperate crates?