The internet was created to share information @Mikey4114. In theory anything you publish to the Internet can be viewed by others. If you are asking if there is a way to help control who can view something on your website then the answer is "Yes". Your solution depends on what platform your website is on. There are different things I'd suggest for WordPress, Joomla, HTML...
If I would have met you at a meet up I'd probably suggest you upload your business plan to Google docs (make it private) and that way you can just email access. You can also see some who viewed details that might be helpful. In Google docs you can also remove/revoke access which can also be helpful? I hope that helps?
...turns out that my two cents is worth less or more depending on the current exchange rate.
roy darling *my posts seem a lot shorter in my head