Assign inbound leads to active users | On shift = Round Robbin leads

[JusinP]

Hey All, 

So we all know that the key to closing an inbound inquiry is to jump on it, and fast. 

let us say for example, John, Mary & Joe are all working the EST region, and a lead comes in from the website, that gets assigned to their team,  but john is actually on leave today, how do we 

A) recognize that he is not around today

B) have the lead round robin'd to the other two 

thanks all 

and do it all automatically?