Maven with Jenkins - Update parent pom version of dependency
You may want to use a dependency range instead of updating the pom: http://docs.codehaus.org/display/MAVEN/Dependency+Mediation+and+Conflict+Resolution#DependencyMediationandConflictResolution-DependencyVersionRanges
For the scenario described in the "Edit" part of the question, I would recommend to put all war files in a single: multi module project.