Help with my dogs infected ears!!!!?

Hello, I have a coonhound with a severe ear infection. The problem is our weimaraner won't stop licking the insides of his ears. Now,coonhounds are already susceptible to ear problems due to their large drooping ears,but when our other dog constantly cleans his ears it makes matters worse. He's been to the vet,twice...all they can do is give him an ointment! But our weim cleans all the ointment out! I know it's due to her always cleaning his ears because every time they start to look better,we catch her licking them again. Is there something I can use that would deter her from cleaning his ears??? The vet is no help,she couldn't tell us anything! What can I do,we try to separate them as much as possible,but we can't keep an eye on them 24/7,that's impossible. Help please!!!