You say "no problem" followed by "tell me what to do". That means that you don't know what to do, which means it is a problem.
If you don't know what to do, I can't help you. I don't even know for sure that it does require a kernel modification: it's possible that there's some process that you can remove that will stop this without damaging anything else. Perhaps. But I do know that OTG requires kernel support, which is why my first thought was a kernel modification.
The problem is that what you are asking is probably quite technical, would require a lot of time for most people to do it, and is not something that very many people want. And that's the catch: when you are asking for something difficult that only you are interested in, it's hard for anyone else to justify spending the time it would need to do it. That's why I asked (rhetorically, I admit) whether you knew how to do those things yourself. If it's important to you commercially, I suggest hiring someone who can do it for you.
I may be wrong: there may be a simple way of doing this (with root, that's a given), and perhaps someone who reads this will be able to tell you what it is. If they can then I'll thank them as well. But I suspect that this is not as simple as that, not something that can be reduced to a few lines of instructions.
