Have you ever heard the saying "keep your friends close and your enemies closer"?
The concept is, you want to know what your foes are thinking and their intentions for your own personal welfare. Taking a call from an adversary or meeting face to face may provide you with information important to your conversations with key principals that might make a difference or affect your outcome in the future. The only way that works is that you have to be very nice, cordial, and just be a listener and not a talker. Meaning, you cannot reveal your emotional feelings about the wrongdoings, hurts, and pains of the past. If that happens it just gives the other side information that may be helpful to them and does not keep them in the dark as to your thoughts or plans. Hard to do I know.
I have had to learn this the hard way in the past.