It won't. Cyrus currently only supports unidirectional replication.
You can make it work (we do), but you need 2 separate instances of cyrus on each machine, which basically means 2 start/stop scripts, 2 different ports/ips for each service, 2 imapd.confs, 2 cyrus.confs, and lots of -C command line params to everything so it uses the right conf file.
Rob ---- Cyrus Home Page: http://asg.web.cmu.edu/cyrus Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html