I want to use on my website digits of postal codes for Belgium/Netherlands for checking out

Question

I'm searching a database of digits codes for Belgium & Netherlands when a person checks out hes/her shoppingcart.

I do did find a map of it but ofcourse it has to be put in a code. (map is 2 digit coded)

For example.

3630 Maasmechelen = postal code 2 digit (36)

Now the 2 digit is 36 but everything with 36 should be possilbe. For example. 3600-3601-3602 (hamlets) and the names of them has to be selected ofcourse.

Another example: 3600 Genk (client should be able to select this in total)

But it takes ages to do it manually so I would like to know if there is somewhere a database of all digits.