Naturally this requires some custom coding. Even if you are not a coder, if you at least have any reasonable kind of coding aptitude, you can probably figure out how to accomplish this. For novice coders, one of the biggest challenges is just getting basic syntax right. Fortunately, the error console tells you where and how you got it wrong. Unfortunately, it will not tell you what is correct. If you have the bulk of your code in place and just need help resolving a syntax error or two, there are lots of people here that can help you out. You need to take the lead with your coding, but you don’t have to go it alone.

For more on validation, with examples, have a look at
https://developer.mozilla.org/en-US/docs/Learn/HTML/Forms/Form_validation

That site is a great reference for all manner of web page coding. Everyone at all levels finds useful information there.