Here's a generic pseudo code process for running multiple OPSUI that point to different OODT deployments.
for contextfile in opsui1.xml opsui2.xml opsui3.xml .. opsuiN.xml; do
1. Create $contextfile in $TOMCAT_HOME/conf/Catalina/localhost (make sure Tomcat is off)
by copying $OODT/pcs/opsui/src/main/webapp/META-INF/context.xml as a starter
2. Change docBase in $contextfile to point to the path to pcs-opsui.war
3. modify $contextfile with different params as needed
4. restart Tomcat
Then you have http://host:port/opsui1/ http://host:port/opsui2/ http://host:port/opsui3/
all accessible and you didn't have to modify code.