We, too, have a dog that licks the others' ears when they start accumulating wax. Lil Belle will lick them to the point of rawness and bleeding if we don't catch it in time.
There is a topical product we use called Synotic (fluocinolone acetonide .01%; DMSO 60%) that we use to reduce the irritation. Don't irrigate the canal with it--we just put a drop on the outside near the opening, then massage it into the chapped area. You'll have to watch that no one licks it off till it's absorbed--and of course, the more you can minimize the licking at any time, the better.
We use Lil Belle as our signal that we've not checked ears frequently enough
She's usually the first to spot problems, although sometimes she licks just cuz
her ears are itchy.
As for the infections, have you tried extra virgin coconut oil, yet? If you search this site using the keywords 'coconut oil' you'll find some interesting threads. It appears to work for some ear problems when used either internally as a supplement or when applied to the ear topically. If your dog has allergies, I'd be inclined to try it topically in the canal instead of as a supplement. Check with your vet first, though, to make sure the eardrum is intact.