John Tran said..
When dealing with team issues, you should start at the top and work your way down. What that means is that you should not get involved with or be concerned about interpersonal issues that do not impact your project’s goals, objectives, and deliverables.
The most advisable course of action with interpersonal issues is for you to take each party aside individually and discuss the problem candidly. Find out what that person is willing to do differently to improve the situation. Do this with each person involved. Then, set a meeting with all parties to discuss the problem and the agreements you’ve forged. By discussing the issues individually, you give each person the opportunity to safely vent their frustrations without adding fuel to the fire. By gathering everyone together after that, you bring people back together to recreate their relationships based on their agreements. If this all sounds a bit too touchy-feely for you, remember that if your team doesn’t work well together, your project may fall apart.
If you’re not comfortable doing these things, get some assistance from your HR department. Whatever you do, don’t ignore these kinds of issues because they will eventually affect everyone on the team, not just the offending parties.