Run Sonar ONLY IF the build is triggered by the crontab of hudson

I want to run Sonar nightly on my components and but I'd like them to be built continuously when there is a SCM change by Hudson.

Currently this works fine for a single project with the option to not launch sonar when the build is triggered by an SCM change. However if I have several maven projects and I use the Hudson option to trigger the build when a SNAPSHOT dependency is built, Sonar is launched for the dependent project.

A good option layout could be : (default depicted)

[X] Sonar :
    Sonar installation :                         _________________
    MAVEN_OPTS :                                 _________________
    Additional properties :                      _________________
    Launch for periodic builds :                 [X]
    Launch for build triggered by a dependency : [X]
    Launch for build triggered by SCM change :   [X]