Healthy individuals do not allow themselves to be drawn into other people’s issues. They may well seek to help that individual solve the problem in a healthy manner but they do not triangulate, nor do they take on the offenses of others. Often in cases like Tom, Mary and Bill, the two with the issue solve the problem but the one who became enmeshed, Bill, continues to carry it in his heart – unresolved - which is not surprising since it was not his to resolve in the first place.
I have watched pastors actually divide boards by choosing to triangulate with sympathetic board members against other board members. Long after the issue is resolved the board remains divided.