I'm trying to figure out how to populate a dropdown box based on another form.

The setup is:

Event Form has typical fields (name, date etc) but also has a multi select lookup from "Class" form.

Nomination Form - has some member details (Full name, phone etc) as well as lookup fields for the Event Name and Event Date from the Event Form.

On the Nomination Form, there is a subform called "Details" - amongst other fields, I have a dropdown on this subform that I want to populate with the options selected in the multi select field on "Event" form.

Is this possible, and if so, how would I go about doing it?

Cheers

Aaron