How to switch friend groups?

I doubt if your first friend group will even realize you are gone . . .

Make the change ASAP.

Surround yourself with people who affirm your interests and values.

You need to ruining all ties with your old friends. Because they are not your friends. And if there were some people in your old group who were your friends you wouldn't be posting here. So get over those people.
Also think why are they excluding you. Were they ever your friends? When they weren't excluding you? What had happened? Just think.
If no idea comes to your mind - move on and good luck!