Has anyone managed to add custom filters to the Timeline component in Freedom UI?

We want to add filters in the same way that you can add them to lookups using code on the page, as there isn't a no-code way to configure additional filters for Timeline components. In our case, it's filtering out non-completed Activity records from the Timeline. We don't seem to be able to using similar methods to lookups though (i.e. adding custom code to the crt.LoadDataRequest handler. Has anyone found a way to add such a filter? It looks like all the Timeline code is in the 9351.xxxxxxx JS file.