At wits end

I wonder if any one else has the porblem of trying to contend with this disease and putting up with a friend or relative that you have to walkon egg shells with!?
For over 10 years now I have had to walk on egg shells with 2 different sister-in-laws. If I do ANYTHING to upset them it goes around the entire family and I am the one who is always blames whether or not it's my fault or not. I cannot say anything that might hurt their feelings even if it's true because the family is so afraid of offending these two even if what I say is true. Funny no one cares whethter they upset me or my entire internal system ! These 2 have had no problem setting off firestorms between my daughter and I, even though what they started were half truths and exaggerated stories!
The thought of being seperated form the rest of my family because of these two is tearing me apart! I need my mom and dad right now and the thought of not being able to be with them on holidays or special occasions has been eating me up all week. 
In dealing with this disease family is all I really have as I don't have friends to turn to.
Has anyone else had to deal with this and if so what did you do?