Maybe this helps a little bit
val String groupIdentifier = triggeringItem.name.substring(0, triggeringItem.name.lastIndexOf('_'))
var StringItem plantNameItem = GRP_PlantName.members.filter[ i | i.name == groupIdentifier+"_Name" ].head as StringItem
var NumberItem plantMoistureItem = GRP_PlantMoisture.members.filter[ i | i.name == groupIdentifier+"_Moisture" ].head as NumberItem
var NumberItem plantFertilityItem = GRP_PlantFertility.members.filter[ i | i.name == groupIdentifier+"_Fertility" ].head as NumberItem