code: public List<GitlabGroupMember> getGroupMembers(Integer groupId) {
          String tailUrl = GitlabGroup.URL + "/" + groupId + GitlabGroupMember.URL + PARAM_MAX_ITEMS_PER_PAGE;
          return retrieve().getAll(tailUrl, GitlabGroupMember[].class);
      }
docs: Gets all members of a Group
  
  @param groupId The id of the GitLab Group
  @return The Group Members