What is the ruling on the profit that the workers' manager gains from the price difference of the distributed piece, knowing that the employer is aware of this?

It appears there is no objection to a worker seeking assistance from other workers. He may hire them for a wage that is less or more than what he himself earns from others. If an individual undertakes to perform a task for a wage, there is no harm in another person accepting to perform that same task for a lesser amount. As for liability, it falls upon the common worker, unless there is negligence on the part of the private worker.