It is the responsibility of the program manager to identify such issues on the onset. It should not become a conflict in the first place. However, if it had happened, then confer with the individual separately, and understand the undercurrent and decide on the solution, and meet with them together, and tell them your understanding of the conflict/issue, and get the issue resolved. Keep monitoring if it really resolved. Without unity among the team members the team can never be successful. Everyone of my projects has been successful, and keeping my entire team or teams together in unison is my strength. If ever conflict arises within a team, in my opinion, the PM needs to tune him/herself.