Is it Islamically permissible to sell customs exemptions for furniture and a car to another person for a sum of money, with the transfer of car ownership occurring after five years?

The customs exemption granted to diplomats is for their benefit during their mission, and they do not own the items. Therefore, they are not permitted to sell these items because it violates the condition and they do not possess ownership, unless the state grants them ownership and allows them to dispose of the items.