Hide Tabs
This project demonstrates how to hide specific tabs on an item form. In this sample code, we hide the BOM and BOM Structure tabs on the OOTB Aras Part form.
The sample code provided in this project...
I think we may actually have a community project that supports your use case in a slightly different way. The Class Picker community project lets you present the user with a dialog to choose the classification of a new item before the item form is displayed. Once the classification has been selected, the correct item form will appear based on the selected classification.