There is a work around for the issue by using a notebook to drive the material.
Create a notebook (the old layout tool).
Add a string parameter to the notebook with the value of one of the material file names. I used MY_PTC_MATERIAL_NAME.
Save the notebook.
When you create your first inheritance model, add all the possible materials that are applicable to the model. [I suggest naming the first inheritance model with a suffix of _master or such to distinguish it as the "template" for other inheritance models.]
In the inheritance model, declare the model to the notebook.
In the inheritance model, create the relation PTC_MATERIAL_NAME=MY_PTC_MATERIAL_NAME
Save the inheritance model.
Use the first inheritance model to create all the other inheritance models you need to create. NOTE: because the model has external dependencies, it cannot be used as a template model (start model). You need to use save-as to create the other inheritance models.
When you want to change the material for all the inheritance models, you need to open all the inheritance models along with the notebook file, update the MY_PTC_MATERIAL_NAME in the notebook, and regerate all the inheritance models.
