If I have multiple accounts, can I set up 1511PIN for each account?

ZONE Telecom > Business > 1511PIN Service
If you have more than one account, you will also see a listing of all the accounts you have currently registered with ZONE1511.
You may create PIN to the respective account by applying the following steps:
1.    Go to our website at http://www.zonetel.com.sg.
2.    Login at the "Members Login Here". 
3.    Under Account Details, click on Manage Telephone Pins.
4.    Select your Account. 
5.    Click Add PINs. 
6.    Click Submit to save the changes.
•    Once you have registered a Telephone PIN for an account, all users using the account's registered numbers will be required to use their assigned PINs. 
•    Once you delete a PIN, you cannot use that PIN again within that account.