combobox dependency

before asking i wanna to show my tables and their relationships(created with ms access 2007) here is the schema :

this is the link :

https://plus.google.com/photos/113802558354450440804/albums/5988059068393888337/5988059068667446962?banner=pwa&pid=5988059068667446962&oid=113802558354450440804

in this case, i create 3 combo boxes in VB2010 :

• cbx_major(binded to MAJOR table)|major_id as the VALUE MEMBER, major_name as DISPLAY MEMBER
• cbx_student(binded to STUDENT table)|student_id as the VALUE MEMBER, student_name as DISPLAY MEMBER
• cbx_course( this is the question )

And here is the scenario :

1. first, i must choose what major is at cbx_major

2. second, the cbx_student will instruct the STUDENT table to select the student_name where major is equal to the selected value of cbx_major and set that query result as the DISPLAY MEMBER of cbx_student(this is done succesfuly without writing any code )

3. (this is the question)then the last, i want to set the cbx_course to display the course_name where student_id is equal to cbx_student.

i have done a lot of effort to do this :

• i opened the combobox tasks menu and choose the student_course table and trying to create the query but it results "the schema returned by the new query differs from the base query"
• i created the query in access by Joinning the table STUDENT_COURSE and COURSE using INNER JOIN then i bind the cbx_course to that query but it results wrong display.
• i opened the xsd file then i create the query there but results wrong result

all those effort does not work. i want to solve this case without writing code but using a technique such setting the taskbar menu, is it possible ? any idea? thanks so much for the attention