Automatically Fill a Second Term Reference Field in a Node Based On Filled Value from a First Term Reference Field Given the following...


A vocabulary (let's call Vocab1) with terms that each have an added term reference field referencing a single term from another vocabulary (let's call Vocab2).
A node that has two term reference fields, the first for a single term from Vocab1 and the second for a single term from Vocab2


would it possible to automatically fill the second term reference field from Vocab2 based on what's is filled in the first term reference field containing a term from Vocab1?
Have look at the following modules

Reference field option limit


  This module allows reference fields of several types to have their widgets' available options limited by the values of other fields in the current entity.


Hierarchical Select


  This module defines the "hierarchical_select" form element, which is a greatly enhanced way for letting the user select items in a hierarchy.