Items:
Switch AC_Power { mqtt=">[control:ha/mod/5557/P:command:ON:1],>[control:ha/mod/5557/P:command:OFF:0],<[control:ha/mod/5557/P:state:MAP(simpleBinary.map)],<[control:ha/mod/5557/P:state:MAP(simpleBinary.map)]" }
Number AC_Mode  <climate>       { mqtt=">[control:ha/mod/5557/M:command:*:default],<[control:ha/mod/5557/M:state:default]" }
Number AC_Temp  <temperature>   { mqtt=">[control:ha/mod/5557/T:command:*:default],<[control:ha/mod/5557/T:state:default]" }
Number AC_Fan   <flow>          { mqtt=">[control:ha/mod/5557/F:command:*:default],<[control:ha/mod/5557/F:state:default]" }
String AC_Zone  <house>         { mqtt=">[control:ha/mod/5557/Z:command:*:default],<[control:ha/mod/5557/Z:state:default]" }
Switch AC_Zone0
Switch AC_Zone1
Switch AC_Zone2
Switch AC_Zone3


:Sitemap
     Group item="HVAC" label="HVAC" icon="climate-on" {
       Switch item=AC_Power label="Power"
       Selection item=AC_Mode label="Mode" mappings=[0="Cool", 1="DH", 2="Fan", 3="Auto", 4="Heat"]
       Selection item=AC_Fan  label="Fan"  mappings=[0="Low", 1="Med", 3="High"]
       Setpoint item=AC_Temp label="Temp [%d]" minValue=18 maxValue=30 step=1
       Group item="Zones" label="Zones" {
         Switch item=AC_Zone0 label="Zone 1"
         Switch item=AC_Zone1 label="Zone 2"
         Switch item=AC_Zone2 label="Zone 3"
         Switch item=AC_Zone3 label="Zone 4"
       }
     }

Rules:

import org.openhab.core.library.types.*
import org.openhab.core.persistence.*
import org.openhab.model.script.actions.*

rule "Aircon Zone Control input"
when Item AC_Zone received update
then
  logInfo("Aircon","AC_Zone got update")
  val String zoneState = AC_Zone.state.toString
  val String zoneState0 = zoneState.substring(0,1)
  val String zoneState1 = zoneState.substring(1,2)
  val String zoneState2 = zoneState.substring(2,3)
  val String zoneState3 = zoneState.substring(3,4)

  if(zoneState != "0000"){
    if(zoneState0 == "1") {
      postUpdate(AC_Zone0, "ON")
    }else{
     postUpdate(AC_Zone0, "OFF")
    }
    if(zoneState1 == "1") {
      postUpdate(AC_Zone1, "ON")
    }else{
      postUpdate(AC_Zone1, "OFF")
    }
    if(zoneState2 == "1") {
      postUpdate(AC_Zone2, "ON")
    }else{
      postUpdate(AC_Zone2, "OFF")
    }
    if(zoneState3 == "1") {
      postUpdate(AC_Zone3, "ON")
    }else{
      postUpdate(AC_Zone3, "OFF")
    }
  }
end

rule "Aircon Zone Control output"
when Item AC_Zone0 received command or
     Item AC_Zone1 received command or
     Item AC_Zone2 received command or
     Item AC_Zone3 received command
then
     val String zoneSwitchState = "0000"
     if (AC_Zone0.state == ON){
       logInfo("Aircon","AC_ZoneX read state")
       zoneSwitchState = '1'
     }else{
       zoneSwitchState = '0'
     }
     if (AC_Zone1.state == ON){
       zoneSwitchState = zoneSwitchState + '1'
     }else{
       zoneSwitchState = zoneSwitchState + '0'
     }
     if (AC_Zone2.state == ON){
       zoneSwitchState = zoneSwitchState + '1'
     }else{
       zoneSwitchState = zoneSwitchState + '0'
     }
     if (AC_Zone3.state == ON){
       zoneSwitchState = zoneSwitchState + '1'
     }else{
       zoneSwitchState = zoneSwitchState + '0'
     }
     if (zoneSwitchState != "0000") {
       AC_Zone.sendCommand(zoneSwitchState)
     }
end