Different HTTP Post endpoint based on fport

Sure, see, e.g., How add data field to URL in HTTP Integration? But even V3 does not support that so don’t hold your breath. Aside: a lot will change in V3, so make sure your application is generic. Like: in the endpoint extract the data you need as early as possible, rather than passing the full JSON data to your actual application code.

(If you need a free a free for 3,333 messages per day third-party service to proxy/route your HTTP Integration payload then maybe a Pipedream example can help.)