code: protected boolean seenByInterconnectedPeers( Set<Long> destinations, Set<Long> origins) {
          Set<Long> seers = Multimaps.filterValues(m_alive, in(origins)).keySet();
          int before = origins.size();
  
          origins.addAll(seers);
          if (origins.containsAll(destinations)) {
              return true;
          } else if (origins.size() == before) {
              return false;
          }
          return seenByInterconnectedPeers(destinations, origins);
      }
docs: Walk the alive graph to see if there is a connected path between origins,
  and destinations
  @param destinations set of sites that we are looking a path to
  @param origins set of sites that we are looking a path from
  @return true origins have path to destinations