Add related records dynamically

I have an application I'm working on with multiple forms/tables that are all related to one another. Some of these forms are extremely short (one is only one field to create a list of "topics" that are shared by two different forms as imported fields).

I would like to let users quickly and easily add new topics from either of the related forms, in-line with filling out the other fields. Some sort of "add new" button that asks for a new topic name and then creates a new record in the "Topics" form and re-populates the imported picklist.

Is that possible? I can't see a way to create records in the scripting documentation, so I'm not really sure how best to go about this.

Thanks!