How to *permanently* give a website permission to autoplay audio?

I have an SPA web app I've built for Safari iOS. One feature I have is that (with user's permission!) I would like to play audio alerts of various sorts based on events that take place in the app. (Think a chat app playing a "message received" sound.)

... again, this would be with the user's permission. This is very much a feature of the app and not nagware or adware.

Currently, of course, this isn't possible. Audio can only be played in response to some user-initiated action, and that "permission" only lasts until the page closes or is reloaded.

So, question: Is there a way a user can permanently give permission to a website on iOS to autoplay sound files?