DSL: How do you remove a CompartmentListItem from the context menu

Question

In my DSL I have four DomainClasses that inherit from an abstract base DomainClass. These DomainClasses can all be items in another DomainClass's CompartmentList. My context menu for the CompartmentList is automatically populated with Add MenuItems for each of the 4 domain classes.

My problem is that I do not want a context MenuItem for one of the DomainClasses. I have looked into the GetMenuCommands method of my CommandSet and only appear to be able to remove All the MenuItems which appear to be populated with Microsoft.VisualStudio.Modeling.Shell.AddCompartmentShapeItemMenuCommand.

Does anyone know how I can locate and remove the menu item I do not want?