Change maxBuiltPerPlayer by a trigger

VictoryFirst

At the start of the game, the Axis powers have only one truck available to them (reflected by <option name="maxBuiltPerPlayer" value="1"/>)

<attachment name="unitAttachment" attachTo="axis-truck" javaClass="games.strategy.triplea.attachments.UnitAttachment" type="unitType">
	<option name="movement" value="2"/>
	<option name="attack" value="0"/>
	<option name="defense" value="0"/>
	<!-- <option name="canBeDamaged" value="true"/> -->
	<!-- <option name="maxDamage" value="1"/> -->
	<!-- <option name="canDieFromReachingMaxDamage" value="true"/> -->
	<option name="isLandTransport" value="true"/>
	<option name="transportCapacity" value="6"/>
	<option name="isLandTransportable" value="false"/>
	<option name="isInfrastructure" value="true"/>
	<option name="isAAmovement" value="true"/>
    <option name="destroyedWhenCapturedBy" value="British:Americans"/>
	<option name="isConstruction" value="true"/>
  <option name="constructionsPerTerrPerTypePerTurn" value="1"/>
  <option name="maxConstructionsPerTypePerTerr" value="1"/>
  <option name="maxBuiltPerPlayer" value="1"/>
  <option name="constructionType" value="axis-truck"/>
</attachment>

At the start of round 7, the axis power should have an extra truck available. So the value needs to change to 2. Is it possible to do so via a trigger?

TheDog

@victoryfirst
Maybe, try the following in a trigger with a condition

<option name="unitType" value="axis-truck"/>
<option name="unitProperty" value="maxBuiltPerPlayer" count="2"/>
<option name="uses" value="1"/>