You can define the following system properties:
Thanks for the info ... and I had feared that.
I did find a doc stating something similar (http://www.jboss.org/community/wiki/TwoClustersontheSameNetwork) and to be honest, am kinda sad that it will cause problems without these changes.
Not that I cannot work around them, it would have been perfect (even if there are downsides) if it ran out of the box without these changes.
Oh well, guess there is nothing we can do.