Not sure I understand the problem, but then maybe I'm not understanding what you mean by "bears at 1 level".
If I have these one to many relationships:
Courses::CourseID = Classes::CourseID
Terms::TermID = Classes::TermID
I implement a many to many relationship between Courses and Terms where Classes serves as "join" table linking the other two.
Does that do what you want here? If not please post an example of what you are having trouble setting up.
thanks for the quick reply Now I can identify better the problem:
my problem concerns auto creating records via other table's records
so how can I do this?
is it clear?
Not really clear as there are a number of ways to create records in a related table. The context is key. From what table do you want to create releated records and in what related table do you want to create them. It sometimes requires a script to create new records, but it depends on what you need and how you choose to design the layout you'll use when doing so.
In general terms, if you enable "Allow creation of records via this relationship" for Classes in the Courses to Classes and also en the Terms to Classes relationships, you can use a portal to add new records in the join table (classes) from a layout based on either one of the other two tables (Terms & Courses). From the Courses layout, you'd be Creating Classes records for a specific course and linking them to Terms. From the Terms layout, this approach would allow you to Create Classes records for a specific Term and linking them to Courses.
Here's a demo file that matches "Contracts" to "Companies" if you rename the three tables, Courses, Classes and Terms, it'll illustrate these concepts.