how to add nodes in constrains? Follow

for example, concept 'business' have a reference to 'Bizcode', I want make it can auto complete when edit the reference bizcode, so I add constrains to concept Bizcode, and I want the context(bizcode) value to auto hint is added by programming(create, new instance). likes:

yes, this can auto hint when edit the bizcode of concept business

 but when I select the value, it cann't add to business's AST.

so how should I do if I want to auto hint/ can selected/add the value to the parent's AST  when edit the reference?