intact bucks trying to mate with a neutered male

Question
Hi can you shed some light on this serious question please and I swear its not a joke.
We have a pack of five rats. We had seven but two passed away from old age. Within the pack our naked rat Harley was very aggressive so after agonizing and trying everything else we'd been advised to do we decided to neuter him. He had a massive post operative infection as he turned out to be allergic to the sutures, he had to have three more surgeries over the next few months and has had recurring abscesses in the groin area, all have been treated with Baytril antibiotics and a number of internal and external ointments. apart from two weeks where he had no option but to be separated in order to recuperate the pack has always been together and has always been normal.
Whats been happening is this,
Three brothers that are now about 10 months old have started to mate with Harley. The biggest brother is the bigggest problem. I originally thought it was just a display of dominance but realised during one play session that it was more as all three brothers are following Harley sniffing and mounting him constantly and to cap it off they are ejaculating and then becoming very confused when nothing is working.
The dominant male called Crackers is almost four and knew Harley before and after the operation as did the three that are causing the trouble. Crackers is now the only rat that can be with Harley, his original cage mates have died so I've separated them into two groups. I wanted to re join the group thinking that it would ease off as they had been apart and as I tried to reintegrate them they were literally humping my hand and fighting to get to Harley who was on my shoulder.
Letting them play together is not an option either as it becomes a very intense session of trying to mate and poor Crackers keeps trying to help Harley by getting in between them all and he can't understand whats going on either.
So I guess my question is ...What the hell is going on? I've asked other forums and my vet and the forums all think its dominance which it is not as I know what that looks like and the vet has checked Harley out for lumps that may be emitting a female hormone and hes really healthy.
Currently they are apart, Crackers and Harley on one level and Othello, Magnus and Bosley on the other but the three are still attempting to get through the bars if Harley is out. They don't try it with each other, they don't try it with Crackers its just poor Harley.
Any Advice greatly received

Julie

Answer
Julie,
This is quite comical when you explain this to anyone. I had a similar issue and my vet made "gay" jokes and told me the same as your vet told you.
I contacted a new vet and this is what we figured.

When you neuter male anything, the testosterone levels decrease And estrogen remains the same level some times increasing. As you know estrogen is the female hormone. Seeing the T levels have decreased in sure your other bucks are confused about his gender. They know its Harley but it doesn't quite smell like him. It will take some time for this to sink in. I would recommend bathing everyone And cleaning the cages. This will rid any oder. If you have vanilla extract take a teeny dab on a paper towel and rub it on their noses. This will make them think they all smell the same. Eventually the smells come back and they realize ok, this is not female even though it doesn't smell female.

If this thrick does not work you can try alternating cage mates. Sometimes if one buck shows sexual interest in another rat it gets the rest fired up. So one by one switch them out with Harley and see who is reacting the worse. Let him do his think as long as he's not harmin Harley and eventually he will get the idea. Then try again and see if they can be together as a pack.

Good luck!