In order for downstream processes such as manufacturing or structural analysis to be successful, you will need to effectively work with mulit-faced polygon models. Normally facet bodies are made up of just one single face. In order to use these facet bodies for more downstream processes, it's necessary to split the mesh-body up.
Realize the next generation of design and engineering with the latest release of NX. Coming January 22nd.
Please see below for the demonstration from user @Paul_Bevan