Is it possible to add an existing Rive animation into the timeline of a new Rive file?

For example, we created an animation for one purpose, and want to impose it in another file, while still retaining its' movement. Is this possible? It seems any way we try (copying and pasting the artboard, copying and pasting the keyframes, etc.) it does not transfer well. We want to nest the artboard in the other one, while keeping the timeline keyframes.

We are using the desktop app, on Macbooks.