Is personal contact information of members in a company protected in court?

If you were in court and the plaintiff wanted information about one of the members in an organization/company, does that information have to be given to them, or is that information kept confidential?Is personal contact information of members in a company protected in court?Only if that information is relevant and needed for the case but if its personal information they will need a court order from the judge. Is personal contact information of members in a company protected in court?If it is relevant or likely to lead to something relevant, it must be disclosed upon being asked.