Since I’m not going to bother with regular updates and support, why not make it free and accessible, right? I just put my Dependent Filters module up on Github for all of you to use.
This module adds on option on the attribute edit view that allows you to select dependencies from a list of existing filters. When dependencies have been set, the filter will not show up on the front end until one of the selected dependencies have been selected.
I hope you find it useful! https://github.com/Prattski/dependent-filters