Hard situation, especially in practices that have been around for a long time and have established teams. Resentment is natural.
I would start by thoroughly evaluating your own performance, to be frank and I hope I don't offend but I've seen a few very nice people go very power when promoted. Not all by any means but some. Once you have identified any negative points about yourself, change them - give it a week as the "new you" and then move onto the next step. Next, informally approach the members you feel have a problem and simpy ask - "is there an issue with something I am doing?" It could be that you are misinterpreting information - we all get things wrong occasionally
Hopefully you can then sort it out between you, in a friendly fashion and find a resolution.
If either a resolution can not be reached or the person denies any grievance but then clearly continues to display behaviour that suggests they do have a problem, the only way forward is formal procedures. Just simply go to the practice manage and owner in your case and give a clear account of what you feel and the evidence you have for what you are saying. Always remember to be prepared. And see what happens....*shrug*
Good luck, I hope that helps.