I'm with Scully.
- If they wont talk to you - then having them talk to your children is going to be harmful to your own relationsihp with your children.
- Don't allow unsupervised visits. No matter what ground rules they agree to - they WILL lie to you and indoctrinate your child. They think they're "saving" him. Besides - you're just a piece of crap, so why not lie to you for the sake of "spiritual warfare".