according to my religious beliefs, forgiveness is always a good thing, even if you dont see the people anymore, it helped me in my life but my situations aren't as bad as yours, it is a good question, if you should try to keep in touch, i would just forgive them in your heart first, then go from there, God will do the rest, just keep praying for them too.in the end you'll be the better person for forgiving them no matter what happens and you can know in your heart you tried.