Billing and Shipping addresses

[Guest]

I am working on an osCommerce site that is heavily modified, and here is the ultimate goal:

 

During the osCommerce checkout process, we need to perform some type of error checking that does the following:

 

1) The user has to use the same billing address as their shipping address.

 

2) The only exception is if the shopping changes their shipping address to a P.O. Box.

 

Can we perform some sort of a test during the checkout process that checks the shipping address vs. the billing address and does the following:

 

1) If the shipping address is different than the billing address, lets do a check for the word "Box" in the billing address field

 

2) If the address doesn't contain the word "Box" then force the user and/or display a message stating that their billing address MUST be the same as their shipping address.

 

Is this possible? Hopefully there's a contribution that can help me?

[Guest]

I wanted to update this posting as my questioning is wrong:

 

I am working on an osCommerce site that is heavily modified, and here is the ultimate goal:

 

During the osCommerce checkout process, we need to perform some type of error checking that does the following:

 

1) The shopper's BILLING address CAN be a PO Box, and they can change their shipping address to something different as most people rarely ship to a PO Box.

 

The error checking will need to do a check for the words "Box" in the billing address field somewhere. If the word "Box" is found, then we will allow the change. Otherwise, we will force them to input a PO Box, and if they don't, we will deny the change.

 

Is this possible?