I have not tried this but assume if you change the line 110 below accordingly it should work.
Change line 110 in datainfo.properties to
where XXX.XXX.XXX.XXX is the URL of your server or "localhost" but I guess that you use different ports such as 8081, 8082 etc for you different instances but I'm not sure how the designer.war would behave. Do you have several different Tomcat installations? In such case you must also install the designer.war in each-
You obviously know much more about your installation and should be able to figure it out. We do not ever use several OC instances on the same instance, if nothing else, for performance reasons we use a separate virtual servers for each study, which makes the customers and auditors happier. You can always ask Tomas (Toskrip, see above) who actually made the .war file available. I only wrote a more detailed instruction.