Using API to pull responses from one form and push as options in another form

1. What is the problem? Be very detailed.
I'm at a very early stage of understanding ODK env, so please let me know if this is the correct place to ask this question. I want to dynamically add options to a drop down list using api. Basically use the api to pull responses from one form, and push it as options in a drop down in another form.

I've read multiple threads here that says linking two forms is not possible (only possible in ODK-X, but not yet experienced enough to go there). But I also read that "Whatever ODK central can do, we can do via API". since central can read form responses and create/edit forms, it should also be possible.

I am reading the API docs but not able to find it. Is it possible/not possible? Is there any 'automated' way of doing this?

2. What app or server are you using and on what device and operating system? Include version numbers.
Not yet setup but reading about ODK central

3. What you have you tried to fix the problem?

4. What steps can we take to reproduce the problem?

5. Anything else we should know or have? If you have a test form or screenshots or logs, attach below.