My father disassociated himself from me numerous times in my life. At one period, it truly was a blessing. I felt no stress at that time, but I wanted to have some kind of a relationship with my dad.
My relationship with my father never really amounted to much, but I now understand that it went that way because of his doing and not mine.
I did feel abandoned when I was younger, and I kept letting him into my life in order for him to make up for lost times. (My folks were divorced when I was 4.) As sad as this may sound, I should have just counted my losses as a kid and kept the divide between us. It would have ended up being a healthier relationship.
I guess you have to look at it this way. If not corresponding with your mother or sisters is proving to be less stressful, and you have no worries about the situation, then I say go with it. Life is stressful enough and added drama is not necessary. If you miss those relationships, YOU have to do something to facilitate any reconciliation.