Currently it is possible to sub-type the WTPart usage link and to create constraints on the sub-typed link to limit it between role A and role B for specific types. Unfortunately there is no possible way to define more than one usage link for a given type having role A. This limits the value of sub-typing the usage link.
1. Allow to have multiple constraints for the role A type in the relationship constraints manager making it possible to have multiple types of sub-typed usage links for a given type.
2. Allow the user to select the type of usage link to create in the UI between role A and B. For customers not interested in this functionality it could be enabled with a preference.