Can different amounts of compensation be specified for different individuals to perform the same designated task?

Primary text

It is permissible to specify different amounts of compensation for different individuals to return the same object, such as giving one person a known amount and another a higher or lower amount. Furthermore, it is permissible to assign one specific compensation for the named individual and another compensation for all other people. This permissibility is analogous to the allowance for differing wages in an Ijara (lease/hire) contract despite equality in the work performed.