Checking/Stopping customer using path

Sphere2


Basically what I first would like to know is how do i get the child for the exit path prefabs for the sphere. The reason i ask that is because the customer follows these spheres. I basically want to be able to have a customer wait behind the customer ordering. so if someone is on the first sphere, how do i first check if ther is an object on the sphere, if there is , stop the customer’s movement until the customer is done ordering