May an agent simultaneously buy a slave on behalf of one principal and sell a slave on behalf of another principal to himself?

Primary text

It is permissible for a single person to act as agent for both the seller and the buyer in a transaction between two parties who appointed him for the respective sides of the contract. This is analogous to a father buying from his son's wealth for himself. The permissibility stems from the fact that the principal has authorized the agent regarding both ends of the contract, thus allowing the agent to execute both actions, provided the agent is not suspected of malfeasance.