as you are part of the family, there really isn't any way out. perhaps you can reduce the conflict by keeping the meeting focused on the topic. when it starts getting off track, steer it back on topic. "we are here to discuss x" keep the focus on the problem, not the person. avoid making you statements. stay in the present, not the past. encourage the use of I statements. remember, conflict takes two, do not engage. if it gets out of hand, say so, and do not participate and dismiss yourself.