*Trigger all if group = the action will trigger on all bookings in a group but only on group bookings. The Invoice Balance trigger uses the booking balance.
*Trigger all Excluding Master except master if Group group = the action will trigger on all SUB bookings, (excluding Master). The Invoice Balance trigger uses the booking balance
*Trigger only master if group = the action will only trigger on the master booking and only if it is a group booking. The Invoice Balance trigger uses the group balance.