I like the idea of giving to charity. Look it up, I am pretty sure there is something in your area. I know that where I live, there is a campaign to help out foster kids getting back to school.
As far as the girls go, it s probably not personal but they are very young and basically torn between a bunch of different people with different agenda. Don't be surprise if they reconnect with you when they are more mature. Right now, it must be really hard on them. Give them some slack and don't build a resentment
