So you are allowing a larger and in your words a snake with a "nasty attitude" to be housed with a smaller one. Not a particularily good idea is it. As you've been told the following around is a dominance display. These are not pack or herd animals that trail each other....these are snakes. You make a broad assumption, while admitting you have no real experience, that they are "very happy". What led you to this specific belief?
But you said yours are happy? So which is it? Are they "happy" as you've previously stated or are you now saying that you aren't able to judge exactly what the situation is for those snakes?
"One particularily well"??? So the other isn't "particularily well" then? Hmmmm....If I notice that mine don't seem so happy down the road I'll seperate mine, but for the time being it seems to be benefiting one particularly well.