Any pratical way of fixing that problem

Not really, because it would require to hack into the ATC system. It's something that has always been like this anyway.
Of course, you could maybe play with the parking radius because, the main rule is, the ATC will direct you to the smallest parking that can handle your airplane so, by adjusting the radius, it's possible to somewhat assign parkings, but it will never be related to your airline in any case.