alternative pom file in modules

[Jagan Padmanabha Pillai -X \(jpadmana - Insight Solutions, Inc. at Cisco\)]

How can I force Maven2 to use an alternate pom file in the modules.
When I call mvn command with the option,  "-f pom_main.xml", only the
main pom is using the pom_main.xml.
In the modules, its still trying to run using the default pom.xml.
 
How can I force it to use alternate pom for all the modules ?
 
Thanks
-Jagan