code: def explode_hostgroup(self, svc_dep, hostgroups):
          snames = [d.strip() for d in svc_dep.service_description.split(',')]
          dep_snames = [d.strip() for d in svc_dep.dependent_service_description.split(',')]
          hg_names = [n.strip() for n in svc_dep.hostgroup_name.split(',')]
          for hg_name in hg_names:
              hostgroup = hostgroups.find_by_name(hg_name)
              if hostgroup is None:
                  err = "ERROR: the servicedependecy got an unknown hostgroup_name '%s'" % hg_name
                  self.add_error(err)
                  continue
              hnames = []
              hnames.extend([m.strip() for m in hostgroup.get_hosts()])
              for hname in hnames:
                  for dep_sname in dep_snames:
                      for sname in snames:
                          new_sd = svc_dep.copy()
                          new_sd.host_name = hname
                          new_sd.service_description = sname
                          new_sd.dependent_host_name = hname
                          new_sd.dependent_service_description = dep_sname
                          self.add_item(new_sd)