I say step away from the computer and forget about Facebook.
Secondly...just my opinion...but people in your family are just as complex as you and have their own needs to fulfil. If that means playing happy families. Then let them, it's actually not up to them to take sides or do anything. (sorry, it's not.)
Get on with your life, see the ones you wish, speak nothing of the others and live a happy life. You've eliminated the ones you don't want to see. Mulling over past hurts is not healthy.