Can multiple annual and hourly grade rates be attached to a single grade code?

Summary:

Currently, each of our grade codes are associated to a single annual and hourly grade rate to account for different in standard working hours per week. As an example, we have a grade 1 code with hourly and annual grade rate values associated with 37.5 standard working hours per week, and a separate grade 1 code for rate values associated with a 40-hour work week. To simplify our grade table, can we associate a single grade code with multiple different grade rates that are tied to different weekly working hours? If so, what are dependencies that we should consider to