execution of contracts

[grynza]

tell me a way to exclude drones from sending resources under contracts?
I would like to set up logistics so that ALL types of materials/goods arrive at the flight control center via a conveyor belt. without drones participating in loading. But I ran into a problem - the flight control center has only 5 inputs, and there are 20+ resources/goods. If I connect all the warehouses, they all simultaneously send goods that are currently unnecessary and clog the feed.

this is a game about automation. it is logical that i would like to achieve full automation in one of the main processes of the game.
at the moment i have connected 15 warehouses to the mission control center, 3 to each entrance. i blocked the supply of materials from all warehouses and turn on the supply only in the necessary warehouses after accepting the contract. and after the contract is completed i turn off the supply again and turn on the outgoing tape so that it dumps the surplus back into the warehouse.
but this is VERY inconvenient. this does not look like automation.