As far as I know, infinite scrolling uses AJAX to get the content. Unless the post ID is being sent by the request on the page there probably isn’t any way to get it.
I’m not familiar at all with how JetPack’s infinite scroll works, honestly, don’t use JetPack and do my best to avoid it. If it’s not being provided as one of the arguments to the function then you’ll probably need to alter the JavaScript that’s making the request to add the post_id.
