[Drago]

I think you've got to assess the situation and make whichever decision you think will best suit your hams. Only you can really know whether they're happy or stressed so I'd just go with your gut. To look at the pros of separation, it eliminates all risk of falling out, your hamsters will be happier and healthier, and it allows them to live a stress free life. Keeping them together on the other hand has quite the opposite effect. In the end, it's a situation where you must do what you think is best. However, just keep all this in mind. Good luck, hope all goes well