Override babel presets to use JSX transformer

[davedbase]

How do I override the babelrc or at least change the Babel JSX transformer preset within a Sandpack instance?

For example say I want to use babel-preset-preact or babel-preset-solid instead of the React JSX transform, how can I override it? I've attempted adding in a .babelrc in the files list but that didn't work.

Thanks!