Hi – great question!
So you want to extend Filter Bar and add an additional filter to achieve this?
If so, yes, that should be possible – but it’s definitely a more advanced customization than we can generally help with here on the forum. The essence of such a customization though would be to write your own filter class extending TribeEventsFilter – and studying the existing Filter Bar code is the best way to get a sense for how it all fits together.
Does that help?