1. Signin your Facebook account.
2. Choose “Account”
3. Next, choose “Edit Friends.”
2. Choose “Create List” button.
4. Choose the chat icon at the bottom right of your screen and the gear image to open the options for chat.
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5. Choose “Limit Availability” and check the list of friends if you want only this group to be unable to chat with you.
6. Choose “Make Me Available To” instead to allow only this group to see you online.
7. Make yourself completely invisible by opening the chat settings box and un-checking the “Available to Chat” option. You will see the list of online friends disappear. See: Can You Identify Who Reports You on Facebook?