If you search "Help" you will find this:

EZ selection of "DrumGrooves" has been added, which are different grooves within drum styles. RealDrums styles with a caret (^) at the end of the name have several "DrumGrooves" available. Now there is an easy way to select the different grooves within the song. Simply right-click on a bar number, and you see a menu of the DrumGrooves within the style. So, for example, you could easily switch from the "side stick/hihat" groove, to "snare/hihat" to "snare/Ride."

This works with RealDrums styles that have variations available. These are RealDrums with names that end with a caret (^) like CountryPopEv16^. This style has 9 Grooves available...