Single Truck to be utilized for two trips in One Day Within Capacity Limits

Summary:

Hi,

We have a requirement where customer wants a single truck to be used in a day within capacity limits for multiple trips.
For example:

Shipment 1 has early pickup time as 2 PM and Late delivery time as 11:59 PM
Shipment 2 has early pickup time as 4 PM and Late delivery time as 3 AM (next day)
For both shipments - late pickup time is 11:59 PM

Carrier has completed the Shipment 1's delivery and returned to the warehouse by 7PM, as the capacities are left for the day and there is still time to pick and deliver the next shipment so same carrier can pick that shipment and deliver, in that way capacities would be utilized less.