maven - multiple repository lookup configuration - maven

Question

I'm using maven v3.0.1 for my projects. I've projects which depends on artifacts from a corporate remote repository. Also I had a local archiva repository in company which hold local artifacts, which are not in to corporate remote repository.
I would like to make the settings.xml in such a way that for all projects, it will lookup for the specified artifact first in the corporate remote repository, if not found there, look up for the artifact in the local archiva repository.
I added local repository in <repository> tag and enabled the profile for that <activeProfile>. But the looking up is not happening as expected. On analysis found that mirrorOf setting plays a role there. Following are my settings.xml.
<?xml version="1.0" encoding="UTF-8"?>
<settings>
<mirrors>
<mirror>
<id>nexus</id>
<mirrorOf>*</mirrorOf>
<url>http://corporate-repo:8081/nexus/content/groups/public</url>
</mirror>
</mirrors>
<profiles>
<profile>
<id>nexus</id>
<repositories>
<repository>
<id>central</id>
<url>http://central</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
<updatePolicy>daily</updatePolicy>
</snapshots>
</repository>
<repository>
<id>spring-snapshot</id>
<name>Spring Maven SNAPSHOT Repository</name>
<url>http://repo.springsource.org/libs-snapshot</url>
</repository>
<repository>
<id>internal</id>
<name>Local Release Repository</name>
<url>http://local-repo:8081/repository/internal</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>central</id>
<url>http://central</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
<updatePolicy>daily</updatePolicy>
</snapshots>
</pluginRepository>
</pluginRepositories>
</profile>
</profiles>
<activeProfiles>
<activeProfile>nexus</activeProfile>
</activeProfiles>
</settings>
How can I modify the settings.xml to do the lookup as I required ? Whether any way to provide two urls in the mirrorOf settings. I tried
<mirror>
<id>nexus</id>
<mirrorOf>*</mirrorOf>
<url>http://corporate-repo:8081/nexus/content/groups/public,http://local-repo:8081/repository/internal</url>
</mirror>
No errors in xml parsing, but lookup is not working. Can any one shed light on how to resolve this issue

Answer 1

I experimented with lot of options and finally resolved by tweaking the mirrorOf settings to <mirrorOf>*,!internal</mirrorOf>
So mirror settings are,
<mirrors>
<mirror>
<id>nexus</id>
<mirrorOf>*,!internal</mirrorOf>
<url>http://corporate-repo:8081/nexus/content/groups/public</url>
</mirror>
</mirrors>
* ensures that for all request except internal repo !internal do lookup in corporate repo. For internal repo, do look up in local-repo configured with repository id as internal