You must (as a compulsory duty) keep in touch with all your relatives even if your parents do not like some of them. Cutting ties with any of your relatives is a major sin. Your parents are not allowed to cause or order any sinful act because the obedience of Allah (SWT) is more important than obeying your parents.
You should not do any thing which degrades your parents like criticizing or blaming them.
You can keep in touch with such relatives who are disliked by your parents, without announcing, to avoid hurting the feelings of your parents.