Have 3 sims dance at same time not working help please

I have that issue with listening to the stereo. I gathered one of my clubs during the party and had them listen to music together, and even though I saw from the animations that there were definitely more than 3 Sims, including my own, listening to music it still said and so couldn't get to gold. :( The task to have 3 Sims dance at the same time did work for me. If you change the volume on the stereo to loud Sims will start dancing autonomously anyway.