opt-groups option for views exposed filters

Hello,

This module is very useful, I use it to activate the "Render parent terms as opt-groups" because I want to force my users to choose the children element of a hierarchical taxonomy and it works like a charm.

However, I want to do the same thing to filters the results in a view with exposed filters. I didn't see any similar options and I think it would be a great addition.

Regards,

Alex