I understand, but there is more at play here, notably the behavior of the Red Cap who originally killed the two that were in our large tank -- I don't want to re-introduce this fish to the 60 gallon because he is showing aggressive tendencies, and I don't want the Black Moor to be rattled any more than she is because she's extremely docile and we're simply lucky to have had her survive this infection.
Do I understand correctly that you have the Black Moor alone in the 60 and the Red Cap along with two other smaller fish in the 10?
If so, the way I look at it, and in my opinion, you have a couple of issues you're dealing with:
First, both tanks are cycling (since both have some measurable aount of ammonia and/or nitrite).
Second, you have the aggressiveness of the Oranda.
The simplest way to minimize the risks associated with both issues at the same time, in my opinion, is to move everyone but the Oranda into the 60 gallon. Three of the four fish will get the benefit of the larger tank's dilution, while the remaining Oranda will also get some benefit from the reduced bioload during cycling since its tankmates will be elsewhere.
This also resolves the nipping problem.
Now, this is just my opinion, but it would seem that combining the goals of having everyone get through the cycling with minimal impact and at the same time separating the Oranda would outweigh any 'loss of community' concerns you have with the Oranda.
Once the 60 is fully cycled, I'd then move the Oranda... and keep a very close eye out for any trouble, especially at first. While goldfish *can* be nippy, agression is unusual. I think it's possible that less than ideal water chemistry in the tank when the Oranda was intially introduced could have stressed the fish and contributed to the the aggressive behavior. Some people get more aggressive when they're stressed too. It's possible you might have better luck reintroducing the Oranda once the 60's cycle is fully established and the water chemistry is stable.
And even if trouble erupts again, you have a cycled 10 to move the Oranda to, and the Moor, after having lived in good and stable water chemistry, will be stronger and better able to withstand any trouble the Oranda might dish out before you have the chance to separate them.
Again, this is just my opinion.
Good luck!