Like Rate Components, Rates themselves can be grouped. Except instead of fees, Rate Groups collect all the varieties of rates, such as overtime or differing units of measure, for a specific position for a specific site.
But rate groups are not associated to suppliers or sites, so rate groups serve as collection objects that are in turn associated to rate grids. This allows the rate grid to show more than just a single rate for a position fulfilled by a supplier at a particular site.
The use of rate groups means that the rate grid contains all rate variances for a position across multiple sites and suppliers.