Maximum Time Constraint Between Itinerary Legs (Using Ground Schedule Shipments)

We are using multi-leg itineraries and most itinerary legs contains at least 1 ground schedule.  We would like to implement a maximum time constraint between itinerary legs but have been unable to find a workable solution.   For example, we have the following scenario we are working on:

Itinerary Leg 1 - No ground schedules on leg.  Product is moved from the order release source location to a bus terminal.  The Buy Shipment has a start date on April 13th and arrives at the bus terminal just before the arrival of the ground schedule shipment that is on Leg 2.

Itinerary Leg 2 - This leg has a ground schedule.  Product is moved from the bus terminal to an airport.  The first available ground schedule is on April 13th and OTM chooses this ground schedule.