How are the properties group and standby.pool used for Brokers created in Fabric?

Issue

• When a broker is created in Fabric it is assigned group and standby.pool properties:

Znode:fabric/configs/versions/1.0/profiles/myBrokerGroup/org.fusesource.mq.fabric.server-myBrokerGroup.properties                                                                                                                L:1 C:1
#Wed May 14 09:00:48 EDT 2014
connectors=openwire
broker-name=myBrokerGroup
config=zk\:/fabric/configs/versions/1.0/profiles/mq-base/broker.xml
data=/Users/jsherman/Development/tools/jboss-fuse/jboss-fuse-6.0.0.redhat-024/data/myBrokerGroup
group=myBrokerGroup
standby.pool=default

How do the properties group and standby.pool affect the broker deployed in fabric?