M5 have a function to create cascading dropdowns for your applications by just providing a simple relationship between the tables.
The first thing needed is a master table for the child table to have the relation with
The child table
In the main application, create the dropdown for the master dropdown and the child dropdown
Then create the behavior for the cascading dropdown, and choose the Action Wizard for the behavior
Choose the Create Cascading relationship in the action wizard
In the dropdown choose the master dropdown and child dropdown in the application
Press OK and the behavior is done.
After that, the cascading dropdown can be tested by running the application
From this view we can see where the relations for the dropdowns will happen.
Images below are the example of how the dropdowns will look like.
