Zoom Webinar Pass Custom Fields or Data

I am working on an integration for my company where we have many recruiters that set up webinars for virtual campus tours. We utilize webinars for these events and I am building an integration using webhooks. This will allow for webinar details to send a webhook payload to an endpoint that will create a Campaign for us in Salesforce.

We need to be able to pass over some custom fields/data about the event that are not relevant to the end-user directly, but determine how the end result gets routed and configured in Salesforce.

For example, we need to pass over a field that tells us the type of recruiting effort this is going to be. Is this going to be OnCampus, or Online.  Rather than having a custom question where we ask the registrant this, we are trying to set it up in a way where the specific webinar they register for has a hidden hardcoded type so they aren't selecting anything on the registration form, but it's a value that is sent over with it and stored in the webinar record. Think of this as adding a hidden input field on an HTML form. It would have a name and a value.

Now, I am aware of the scheduling tracking fields, but these look to be account level specific with limits of 10 per account. I need something more at the webinar/meeting level. A good place for this could even be the custom questions section on the registration form with a type of "hidden" where we just provide a name and a value, that way its already part of the "form" and sent over with submission.

Perhaps as an end-user, something like this exists but I am not aware of it or its not currently enabled.
Does anyone have any ideas?