I have 3 IEnumerables that I want to iterate over. I want to do something like this:

IEnumerable<Car> redCars = GetRedCars();
IEnumerable<Car> greenCars = GetGreenCars();
IEnumerable<Car> blueCars = GetBlueCars();

foreach(Car c in (redCars + greenCars + blueCars)) {
    c.DoSomething();
}

...

The best way I can think of is:

...
List<Car> allCars = new List();
allCars.AddRange(redCars);
allCars.AddRange(greenCars);
allCars.AddRange(blueCars);
foreach(car in allCars) {
    ...
}
...

Is there a more concise way to do this? Seems like combinding IEnumberables should be trivial.