public int numOpenings(Background b) {
    final int nO = super.numOpenings(b) ;
    if (b == Background.VETERAN) {
      return nO + 2 + structure.upgradeLevel(SECURITY_MEASURES) ;
    }
    if (b == Background.TECH_RESERVE) {
      return nO + 2 + structure.upgradeLevel(LOGISTIC_SUPPORT) ;
    }
    if (b == Background.AUDITOR) {
      return nO + ((1 + structure.upgradeLevel(LOGISTIC_SUPPORT)) / 2) ;
    }
    if (b == Background.STEWARD) {
      return nO + ((1 + structure.upgradeLevel(GUEST_QUARTERS)) / 2) ;
    }
    //
    //  TODO:  Return the amount of space open to hostages and guests as well.
    return 0 ;
  }