I'm planning to create a group chat to bully a toxic person.
Why don't you like this person?
She's just a loser and she can't keep a conversation going
It is wrong to bully anyone.  You do realize you are doing the same against her by forming this group.
Once it's done, it's done.
Yes, but you haven't done it yet so I would urge you to reconsider. If you have a problem with someone, you should talk to them about that problem. Bullying them won't solve anything.