def METHOD_NAME(self, group, target):
    new_target = []
    for user in target:
        pg = self.get_primary_group(user)
        if pg == group:
            continue
        new_target.append(user)
    discarded = set(target)-set(new_target)
    if len(discarded) > 0:
        pinfo("group %s members discarded: %s, as they already use this group as primary (you may want to change your rule)" % (group, ', '.join(discarded)))
    return new_target