Unfortunately, it is not possible to deploy the Http Receive Location on a non-BizTalk Server.
There are two options to avoid publishing the BizTalk Server’s IP address directly to the internet.
1. Write your own Http receive software that can be deployed to the IIS server. This will simply forward all requests to the internal BizTalk server receive location. You can use any BizTalk supported protocol here.
2. Use a reverse proxy server that will map the internal BizTalk Http Url externally. (f5.com/…/reverse-proxy)