Meg, Thanksgiving is just around the corner. Maybe you could write them short notes sharing a memory, thanking them for the friendship they brought into your life, apologizing for things you might have done to hurt them, and telling them you're in recovery now and that you miss them. They may not respond, but airing the feelings may give you some closure, and your honesty may bring some communication from them. If they completely ignore the notes, then you can move on at least knowing you tried your best to fix things.