Plots - Query a plot has been set

[MicroTrends]

This is a little off the beaten track but say you have an indicator which has 3 plots - which you want to query from another module

Indicator: IndX

Plots:
up
flat
down

These are set according to some unknown method.
For any given indicator - Is it possible to to query which one was plotted...

e.g

if (indX.up was set)
{
processUp();
}
else if (indX.flat was set)
{
processFlat();
}
else if (indX.down was set)
{
processDown();
}

Maybe it is possible to bind an event handler to fire when the plot has been set?

[NinjaTrader_Bertrand]

I think you could use the ContainsValue to check if for the underlying Values series a value has been set, then expose this, too to make it accessible from the other indicator.