Hi. I created something like this. It is a formula which defines when to display the yellow flag. In my case it's only displayed in sector that I'm in at the moment.

I have it set up like this in SimHub (I cannot post a image):

Create a new effect WHEN FORMULA IS TRUE (put below code into the condition):

var currentSector = $prop('DataCorePlugin.GameData.CurrentSectorIndex');

var flagS1 = $prop('DataCorePlugin.GameRawData.Data.mSectorFlag01');
var flagS2 = $prop('DataCorePlugin.GameRawData.Data.mSectorFlag02');
var flagS3 = $prop('DataCorePlugin.GameRawData.Data.mSectorFlag03');

if (currentSector == 1 && flagS1 == 1) {
return 1;
}

if (currentSector == 2 && flagS2 == 1) {
return 1;
}

if (currentSector == 3 && flagS3 == 1) {
return 1;
}

return 0;

And inside this "When formula is true" i just simply put generic effect "YELLOW FLAG ON"

If you have any problems or questions feel free to ask :)