I would have thought this was self-evident from the structure of the EAR's application.xml file, but here's an example of how it looks with two WARs:
xml version="1.0" encoding="UTF-8"?>
<application>
<module>
<web>
<web-uri>/directory/of/war1</web-uri>
<context-root>/war1</context-root>
</web>
</module>
<module>
<web>
<web-uri>/directory/of/war2</web-uri>
<context-root>/war2</context-root>
</web>
</module>
</application>