Dynamic dropdown filtered by relations of another field

Hi Autovrata,

Thanks a lot for the epic work you did on this plugin. I enjoy using it a lot, and dynamic lists are a bless to work with.

I was wondering if the following would be possible:

One custom post type exists: ‘trainings’. Each training has a couple of possible starting dates. I’d like a contact form to dynamicly present the existing trainings, and when somebody did that, I’d like the available dates to appear in a next dynamic list.

Would that be possible? And if yes, how would I proceed best? I can think of either:

– making another custom post type ‘training-dates’ and have a one to many relation between them: One ‘training’ can have multiple ‘training-dates’ assigned to it.

– making a custom taxonomy ‘training-dates’ and assign possible dates to each ‘training’

– making a repeated custom field ‘training-dates’ containing the possible dates per ‘training’

Would it be possible in any of these scenarios to have a second dynamic dropdown in a form that populates according to the selection in a first dynamic dropdown?

Thanks an awful lot for thinking along!

Best regards,
Rene.