Clean shutdown after xtrabackup completion

I’m using xtrabackup to do an online data migration between 2 servers (xtrabackup piped to another server). The complication is that we have 3 slaves that i’d like to keep in sync during the process. The easiest way I can think of is to have xtrabackup shutdown the master server after the backup completes so I end up with 2 servers that are identical, then i can just bring the new master online and tell the slaves to talk to it without having to refresh them. Is this possible?