Retrieving account numbers

Dear List,

I have the following requirement :

there is field called bill account which is 9 digit character.
ex : 691909909, 967810123 etc.

and the requirement is that the script should process only for account numbers starting from 69 and 96.

how to acheive this using shell script ? it is written in ksh
the requirement is also such that the user should be able to add another account tomorrow without changing the script. The account numbers should be parameterised

Santosh