Question 1.
Assuming you are setting up a file jetty.xml, then you will have something that looks something like this:
<Call name="addConnector">
<Arg>
<New class="org.eclipse.jetty.server.nio.SelectChannelConnector">
<Set name="host"><Property name="jetty.host" /></Set>
<Set name="port"><Property name="jetty.port" default="8080"/></Set>
<Set name="maxIdleTime">300000</Set>
<Set name="Acceptors">2</Set>
<Set name="statsOn">false</Set>
<Set name="confidentialPort">8443</Set>
<Set name="lowResourcesConnections">20000</Set>
<Set name="lowResourcesMaxIdleTime">5000</Set>
</New>
</Arg>
</Call>
You will need one connector for each IP address that you want to listen to. So, just duplicate this section as many times as you need. Then for each of them replace the line
<Set name="host"><Property name="jetty.host" /></Set>
with
<Set name="host">www.xxx.yyy.zzz</Set>
where www.xxx.yyy.zzz is the IP you want to listen to.
Question 2.
Cm.