If you start putting crabs in different tanks, it's very very likely that you'll have some disappear, either digging down or hiding

You could set up some sort of playpen (which might be beneficial if you feel like your tank is small and the hermies need some excercise) but if you can, try to keep the area warm and moist. I did this in my room last summer by putting it near the space heater and spraying the area

But I wouldn't recommend doing this often, removing a hermie from their habitat and putting them in a new area is very stressful, it won't 'smell right' to them and they may panic (panic is sometimes interpreted as excitement, when a hermie starts running around and going nuts) It's like being uprooted and put in a new home, they don't understand that they'll be back in their tank soon and that it's supposed to be for fun.
And of course you run the risk of fights, it's recommended to bathe new hermit crabs when introducing them to the main tank to make them smell neuteral so the other crabs aren't as likely to start a fight. But crabs from two different tanks will smell eachother and see the other crabs as strangers. This can be helped by bathing everyone first, but repeated baths are stressful and mess around with their shell water balance.
All in all, it's alot of effort and stress for very little benefit

I think you and your crabbies would just be happier in their own tanks. Maybe you could place the tanks beside eachother once and awhile (a 10g is certainly easy enough to cart around) and curious crabs can check eachother out.