Truck gate is Target. They fall under the Target Security Services umbrella. They used to be the same exact team as AP but now are technically unique roles.
Dispatch is also Target. As is packet office.
You do however have representatives from trucking companies on site that handle their side of business too since Target does not have trucker employees, except for the Yard drivers. But all OTR truckers are contracted. Even the ones with dedicated routes to specific stores.