Congratulations,
I'd talk to all three and state quite frankly,
"Some of you, or all of you, might be pissed cause I got the promotion. Frankly, I'm a little surprised myself. However, if you feel bitter because of this please keep in mind that I was not the one who made that decision. The decision was made by both our bosses. I'm no idiot, as are none of you, so I took the promotion - as would all of you done as well. Save your bitterness for those who chose me, not for me myself." "It would be like hating someone cause they won the lottery. What would they do? Give the money back cause someone else deserved it? Let's be adults here and accept the situation. I'd like to think that if the situation was reversed, I would accept one of you as my boss/leader/whatever you are now. If you can't accept that and feel bitterness towards me, well you're just a fuckin baby then. Live with THAT."
"That's my speech, I'm sorry if it comes off as patronizing to you all I'll try NOT to be that way as a leader."
"Hey you guys wanna see some naked pictures of that secratary on 4th?"