Restricting a Custom Form by a customer's postal code?

Hello,

My wife and I own and operate a small micro-coffee roaster in our community. We sell our coffee beans online and offer a free local delivery option for the two communities located in our immediate zip code. I have seen that I can create a custom form to be completed at checkout, but is there any way I can develop a custom form that will only collect information from the customers who are eligible for the delivery offer? We would like to be able to have the form request a window that would work best for us to delivery their order so that we can ensure they receive their coffee. The preference is that this information can be collected at checkout and send to us automatically so that we can fulfill their request without having to reach out through email to gather a time we can show up. Is this something we could accomplish with custom code or can we use a workaround on the platform?

Please help as we are live and would like to find a fix as soon as possible for our problem.

Thank you,

Please see Adding a delivery option. Not sure it will do all of what you need.

Just a note. The checkout page can not be altered with custom code. It is a SS security feature.

Let us know how it goes.