You have a couple of choices.

You can, as per phydeauxarff suggestion, modify your database so that, when entering tracking numbers, you also specify the carrier which they belong to. For instance, when you enter a code such as GE732387457WW (invented) you assign it manually to TNT.

As an alternative, you can just enter the tracking numbers and have your software determine which carrier they belong to. Just to stay with TNT, you know that a number which satisfies the regex:

/^GE\d{9}WW$/
[download]

is theirs. You can do the same for other carriers. If you choose this way, remeber that some carriers (i.e. UPS) have more that one format for their tracking numbers.

Michele.