Help with splitting a mesh controlled by an armature

I’m rigging a Minecraft villager, but having an issue with the robe. Rather than use cloth simulations, I decided to parent it (with automatic weights) to the armature and it works almost perfectly. However, it sometimes dips underneath the mesh. Is there a way to “open” the bottom part once the legs get too far away from the body? Sorry if this is a dumb question, I’ve just never really done anything like this. Thanks for your time!

Here’s the .blend file: villager.blend (1.43 MB)