Regardless of religious confidentiality, forcing you to go to Narc or Alc meetings COULD be interpreted as violating Hippa. Hippa is federal law. With regards to medical information, it protects your privacy. Hippa has guidelines that keep your medical information private. Be forcing you to attend these meetings where you may run into people you know or people who you may have to deal with in the future in your public life, they are forcing you to publicly reveal your medical history (and that's a Hippa no-no).
Also, just something to think about: if you are in rehab b/c it was court ordered, the rehab facility/personnel may be taking liberties with peoples rights (like forcing them to attend a public meeting) because most people are just doing whatever they are told to keep from violating the court order that would send them to jail. Some sneaky facilities & their personnel know this, so they kinda push "the little guy" around.
If you are looking to sue, the suit would not fall under religion, it would fall under Hippa & medical confidentiality.