public static String getPropertyGroupId(final ConfigurationMetadataProperty prop) {
        if (isCasProperty(prop)) {
            return StringUtils.substringBeforeLast(prop.getName(), ".");
        }
        return StringUtils.substringBeforeLast(prop.getId(), ".");
    }
Gets property group id.

@param prop the prop
@return the property group id
support/cas-server-support-configuration-metadata-repository/src/main/java/org/apereo/cas/metadata/CasConfigurationMetadataRepository.java