In order to Create Group chats List with Online User List. Kindly follow the below mentioned steps
Login in CometChat Admin Panel
From left side menu, click on "Settings->General"
In "Groups Chat" section search for "Show only online users in groups" and click on "YES"
Click on "Update" Button and from the left menu, click on "Clear Cache"
Now you can see Group Chat List With Online User List.
We believe the above-mentioned steps were helpful to how to create group chat list with online user list only.