[Captain Kwok]

I never really thought about it before, but you could probably use the same family number for all those types of components and it would prevent stacking.

For some reason I was thinking that if you gave the same family number to say, both ECM and Combat Sensors - it would cancel one of them out. But of course it wouldn't since they are different abilities. So, as Fyron suggested give them all the same family number and just separate them with another component.

Something like this might work where x represents the same family number:

...Combat Sensors (x) - Multiplex - ECM (x) - "Scanner" - Federation Sensor Array (x) - Klingon Target Sensors (x)...

Try arranging the sensor components like that and see if it works.