Groundhogs

A groundhog has been spotted wandering about the area, and I can only assume he's a relative of my groundhog brother and sister, Gregory and Gianne Groundhog. Does anyone have any suggestions as to how I can prevent a new guest? The fence won't work since I've learned that groundhogs can scramble over them despite what some books might have you believe and goodness knows if I don't watch the door every minute, my siblings will just throw it open for him. I really hope his paws don't get tired, too, so he has to wave down a cab. It's always such a pain and I'm sure he'll expect the residents here to pay his fare too!