Build a Guild! Better trades from larger professional communities

Make the player create more villagers with the same profession to get the best trades. A villager working by themselves might only give lower level trades. A group of villagers of the same profession with their workstations all within a certain distance of each other could unlock the higher level trades. You have to have a certain number of villagers with each experience level to unlock the best trades for that tier. For example, one master librarian by themselves might only be able to trade mid level enchanted books but maybe a group of 16 librarians with at least 4 of them masters whose lecterns are all within a certain range of each other unlocks the probability of trading max level enchanted books for all of them.