Sorry, but this just isn't how it works, especially since Bosman where player power is significant (almost to a fault). If a club wants to move a player on and the player doesn't want to leave he just doesn't sign any deal. If a player wants to leave and the club doesn't want to let them then the player can run the contract down and get a tonne more money as a free agent. This is pretty rare in fairness as keeping a disinterested player is not great policy. So say a club is trying to sell a player for either reason and the they get one offer they're happy with, but its from Newcastle. The player can easily say "nope, not going to them", then the club can look at the next level of offers, or keep the player and they'll run the contract down.
To suggest that the top players commanding offers from Newcastle are poor innocent pawns with little to no choice in where they choose to sign and play is laughable, I'm sorry but it just is.