@PEntity class MyEntity {

    @Variable(listeners = FireToLavaAndSmoke, FireAndWaterToSteam)
    Fire fire; // genuine variable
    @Variable(listeners = FireAndWaterToSteam)
    Water water; // genuine variable

    Lava lava; // shadow variable depends on fire
    Smoke smoke; // shadow variable depends on fire

    Steam steam; // shadow variable depends on fire and water
}

@PEntity class MyEntity {

    @Variable
    Fire fire; // genuine variable
    @Variable
    Water water; // genuine variable

    @CustomShadowVariable(source = {fire}, listener = FireToLavaAndSmoke) // Workaround: also affects smoke
    Lava lava; // shadow variable depends on fire
    @CustomShadowVariable(source = {fire}, listener = FireToLavaAndSmoke) // Workaround: make this a dummy
    Smoke smoke; // shadow variable depends on fire

    @CustomShadowVariable(source = {fire, water}, listener = FireAndWaterToSteam)
    Steam steam; // shadow variable depends on fire and water
}