Create Event Program Items/Registration Options using REST API

Is there any way to use the REST API to add registration options and program items to an event?

I am searching through the documentation now and did not see much related to it.

I've tried using GET https://{{URL}}/api/Event/TESTING123, adding a program item, and then using PUT https://{{URL}}/api/Event/TESTING123 but the program item does not get added.

I've also tried adding an item to iMIS using the same item code and then adding the program item, but that did not work either.

Any assistance would be greatly appreciated!