Two Character Controllers Colliding...

Hi, I am making a Diner Dash sort of game, but I want obstacles to come and go that I need to avoid with the waitress. In the case we 'bump to each other' or 'collide' I want them to each get affected and maybe move back a certain distance. Kind of like falling down and back? That's what I need help with!

Obstacles go left to right or right to left and they move with Character Controllers (set a target, left or right, and CharacterController.Move to there). They also have RigidBody as one of their components.

My waitress can move anywhere in the floor. You control her with a the arrows using the CharacterController.Move as well. She also possesses the Rigidbody component.

Any ideas?

Thanks for your help and time!