networking – how to make a pc to be connected with another pc directly, while still let it connect to the internet via network cable

I have my pc which is connected into our LAN via a network cable, and through which internet can be visited.

Now one of our teammates has his pc, which has no right to connect to our LAN.

Problem is that my teammate and I are now developing a web application, I build the backend and he build the frontend, and we need to communicate with each other through predefined http RESTful api.

I need to communicate with my teammate, while still can access our LAN. What is the best practise to do so? Both of us are using windows.

I tried to open a 360wifi, which can make my laptop pc to setup a wifi, and my teammate’s laptop can access this wifi can visit the internet. But he cannot visit my backend service by the ip address of my laptop in the LAN network(ping returns error.).

I guess I need two network card, one for our LAN, aonther for my teammate, we can connect with each other via directly network cable connection.