Today i saw 5 coordinated greifers all working together to destroy hard work they joined around the same time and all went to the same map and attacked the same thing and once satisfied they moved on to the next target. if anyone nos a good way to stop this or knows howto help.
Ban, then undo. If they by chance have the same IP, ban it. Not really much else we can do.
i wish there was a quicker way to ban because 3 GREIFERS had random and long names like bov1bt4t7bt74 and so on
Well, as long as you are in the same map as them, you can simply click their name by holding tab. This helps with strange names a lot. To help keep them there, you can /jail them so they can’t make any changes while you undo and ban them.
This can help:
ban [#/@] [OP+] - Bans without kicking them.
* /ban # <player> stealth bans.
* /ban @ <player> total-bans (undoes and IP bans).
Silently ban them so they don’t know they have been found. You can also /hide while you do it.
The /ban @ command is very powerful. It undoes 5400, ip bans, and bans them in one go.
what i like to do is silent ban them and undo their grief, that way they cant make changes to what they have done but they also think that they are still causing annoyance, but ive found with bots, if they are banned, they return to the spawn point and log off, im assuming that they are designed to get rid of EVERY block that is in the map then go, after banning, they no that no block changes can occur and ‘shut themselves down’ in a sense
unfortunately though, 5400 is quite often not enough 
OMFG MY HOTEL WAS A TARGET!