Yes, this is why the prompt mentions a group of four! I actually debated for quite some time whether to say it was a group of three or group of four and ultimately landed on four because I didn't want a bunch of angry comments along the lines of "what about Neil Young?!"
Saw CS&N at the NYS fair in 1987. Neil Young was playing the Carrier dome that weekend and word on the street was he was going to show up and jam with them at the fairgrounds! Never trust word on the street. Great concert though.