API to schedule temple appointments?

Is there any kind of API (RESTful) to schedule temple appointments?

Problem to be solved: I'm my ward's temple and family history leader and I've struggled to get the ward engaged to come to ward temple night. I think part of the problem is that having to go online to schedule an appointment is an extra task that gets in people's way. I'd love to automate this somehow, perhaps by writing a mobile app for the ward (I'm a professional software developer) that would pop up reminder notifications on people's phones and let them schedule an appointment for ward temple night by simply clicking a button.

The obstacle: Third party applications are not allowed to use Church Account credentials. Other than FamilySearch, no third party APIs have been allowed.

About all you can do is create a home screen shortcut to the relevant web page. If the member has their login memorized by the browser, it should be pretty easy to login.

Thank you for the reply.