What you need to search is how to embed an iframe on Facebook, and you will find something like this:
https://www.loghound.com/content-marketing/how-to-easily-add-an-iframe-reveal-tab-to-your-facebook-page-no-php-required.html
Since a Virtual Tour is embedded via an iframe on a 3rd party website the above article is relevant about how to add a virtual tour to Facebook. Now if you read the article you will find that you can not add the iframe directly in the feed, just to a Page, and I think the Page needs to have 2000 likes ...