Fracture Demolition Software, makers a procedural event driven destruction tool Fracture FX for Maya, have posted a look painting colored clusters in Fracture FX which will give you control on your breaks in your simulations.
covers some events and filters designed to give you ultimate control on how and when to break/separate clusters
Fracture FX for Maya will allow you to paint clusters with Maya’s Artisan Tools, and allow you to manually select fragments, and use voronoi cells, volumes and meshes. Although still mentioned as being in “soft Release”, FractureFX is an extremely capable destruction plugin for Maya supporting Voronoi, Planar, and Noisy Splitting Plane breaking styles.
Fracture FX supports all platforms for Maya versions 2009 to 2012, Linux, Mac, and Windows on 32 and 64 bit. Check out FractureFX for Maya for more information