JXTA Configuration

All,

Can somebody please explain the relationship between the JXTA_HOME env 
variable the creation of a new NetPeerGroup?

If I'm creating several JXTA nodes inside a single JVM do I have to set the 
JXTA_HOME env variable before starting each node? 

Why is there no way to pass the JXTA_HOME--or even the JXTA 
configuration--to the factory methods that create the NetPeerGroup?

Also, I've read in several places that multiple nodes--in addition to having 
separate home directories--must have different ports specified to bind 
against. What ports are these? How can I customize these ports? I don't see 
any such properties in the net.jxta.ext.config.Configurator class besides:

private java.net.URI home;
private java.lang.String descriptor;
private java.lang.String peerName;
private java.lang.String peerDescription;
private net.jxta.ext.config.Trace trace;
private net.jxta.peer.PeerID peerId;
private boolean isSecurity;
private java.lang.String principal;
private java.lang.String password;
private java.net.URI rootCertificateAddress;
private net.jxta.impl.protocol.PSEConfigAdv pse;
private java.net.URI peerProxy;
private java.net.URI rendezVousBootstrap;
private java.net.URI relaysBootstrap;
private boolean isRelaysDiscovery;
private java.net.URI reflectionBootstrap;
private java.util.List transports;
private net.jxta.impl.protocol.RelayConfigAdv relayConfig;
private int endpointQueueSize;
private boolean isProxyEnabled;
private net.jxta.impl.protocol.RdvConfigAdv rdvConfig;
private java.util.List optimizers;
private java.util.Map customParams;