Private invitation links for private opportunities

It would be great to have the ability to have a private invite link for opportunities that you don't want every member to have access to. For instance, we have projects that are going to be completed by a church or a business and they are going to provide all the volunteers. We would like to send them a link so only people with the private link can sign up. Other members can still see the project but see that it is private and not available for sign-up