I am not sure if this is possible, but it would make my life much easier if it is. 

Cameo Systems Modeler 19.0 SP4 (soon to upgrade to 2021x if that makes a difference)

I have a shared framework project (metamodel) that is used across several projects to define custom elements.

Some elements in that shared project have enumeration properties, but some of the projects need a few extra options in those enumeration lists (but not all of them). 

Is it possible to do a customization/extension/specialization in a specific project that uses the framework as a project usage? 

I understand I can do a specialization on an enumeration to inherit the literals, but this doesn't work in my case, because it would require me to edit the element to change the Type of the property from the initial enumeration to the specialized one at a project level--which doesn't work because it is pulling those elements in as a project usage so they aren't editable. 

Any suggestions or help is appreciated.