Here's what I've put together, as a way to determine whether I've understood the requirement, i.e., a view on a multi-module Maven project that incorporates subprojects within the node hierarchy of their parent:
Above is the multi-module JAnocessor project, while below the NetBeans RCP CRUD sample application:
Here you see another example, part of the long list of modules constituting AgroSense, the 2012 Duke's Choice Award winning open source farm management system, where it's now possible to work on all the projects without needing to open any of them, once the parent project has been opened:
And here's the location of the plugin:
Note: Despite what it says on the page above, you MUST have NetBeans IDE 7.3 Beta or later to use this plugin.