Combine time, a region and reinforcements

Write the objective as measurable conditions

The objective requires 20 seconds since map start and two defenders staying in a region for 3 seconds, followed by one reinforcement group, separate the clock, detector and result so each step is inspectable

Keep the detector focused on units and area

The unitDetect rectangle defines the region, team selects the side and onlyWithTag matches v08defender in core, minUnits is two and warmup requires the condition to remain true, ensure the map contains team 0

<object name="v08_zone" type="unitDetect" x="200" y="200" width="160" height="120">
  <properties>
    <property name="team" value="0"/>
    <property name="onlyWithTag" value="v08defender"/>
    <property name="minUnits" value="2"/>
    <property name="warmup" value="3s"/>
  </properties>
</object>

Choose all conditions or any condition

activatedBy connects the clock and detector to the reinforcement object, allToActivate true requires both and repeatCount one limits activation, omitting the all-condition requirement can allow either upstream event to trigger early

<object name="v08_reward" type="unitAdd" x="400" y="280" width="20" height="20">
  <properties>
    <property name="team" value="0"/>
    <property name="activatedBy" value="v08_clock,v08_zone"/>
    <property name="allToActivate" value="true"/>
    <property name="repeatCount" value="1"/>
    <property name="spawnUnits" value="rwa08Firecontrol*1,rwa08Skyguard*1"/>
  </properties>
</object>

Observe missing and satisfied conditions

Merge the XML objects into the triggers layer of a valid map copy, the fragment is not a standalone map, observe time alone, then one vehicle, then two vehicles held for three seconds, map links and unit action references are separate systems