ServerPilot configures your server to listen on all interfaces, so if your server has multiple IP addresses, you can access it from all of them.
Knowing this, ServerPilot also makes it easy to use a specific IP address for a particular app.
First, make sure the app has a domain added to it in ServerPilot.
Then, configure your DNS for that domain to point to the specific IP address you want it to use.
Now, requests for that domain will use only the specific IP address of your server you configured through DNS.