There are several different ways to resolve conflicts, open-door policy, peer review, mediation, arbitration. Depending on the personalities and the problem going on would help determine which one should be used.
EMOTIONAL HOOK:
How would you feel if you were having issues with another employee and you boss didn't have an open door policy, what would you do, who would you talk to?
KEY POINTS:
The best policy is for the HR person to be able to do all of the different ways of resolving conflicts. You do not want to be stuck in a one way thing, and because of that you are unable to help some employees because you way does not work for them
FACILITATED QUESTION:
What conflict resolution works best for you?