Group instruments in mixer

When listening to SATB voice parts on the playback to hear if the harmony is right, I usually use the "Choir Ahh" sounds. Sometimes, I can better hear the distinctions between the parts using a piano sound or some other sound. However, when I go into the mixer, I have to change each instrument sound individually which is time consuming (the process of scrolling down to find the different part). Is there a way to group the parts in the mixer so that you only have to change instruments one time for all four voices? I tried this by using the shift key and the control key, but it didn't work.